Muscle exercise and rehabilitation apparatus

• US 4,691,694 A
• Filed: 09/15/1986
• Issued: 09/08/1987
• Est. Priority Date: 11/29/1984
• Status: Expired due to Fees

• Current Assignee: Biodex
• Original Assignee: Biodex
• Inventors: Boyd, Robert L., Gezari, Daniel Y., Krukowski, Richard
• Primary Examiner(s): Picard, Leo P.
• Application Number:
  US06/907,392
• Time in Patent Office: 358 Days
• Field of Search: 128/25 R, 128/256, 128/26, 128/363, 128/364, 272/129, 272/130, 272/116, 272/DIG. 5, 272/DIG. 6
• US Class Current: 601/34
• CPC Class Codes: A63B 21/0058 using motors
• CPC Class Codes: A63B 2220/16 Angular positions
• CPC Class Codes: A63B 2220/54 Torque
• CPC Class Codes: Y10S 482/90 Ergometer with feedback to load or with feedback comparison
• CPC Class Codes: Y10S 482/901 having computer circuitry

Abstract

A muscle exercise and rahabilitation apparatus includes a movable fixture against which a force can be applied; a servo motor having an output shaft coupled to the fixture; a strain gauge effectively coupled between the output shaft and the fixture for producing a load signal corresponding to the force applied to the fixture; a speed detector for producing a velocity signal corresponding to the speed of the fixture; a closed loop servo circuit for controlling the motor in response to the load and velocity signals to regulate the velocity of the fixture; a limit circuit for preventing movement of the fixture past opposite limits; a storage circuit for storing limit signals corresponding to each limit; a limit setting circuit for enabling the storage circuit to store each limit upon movement of the fixture thereto; a position sensing circuit for producing a position signal corresponding to the position of the fixture; a deceleration circuit for slowing down movement of the fixture as the fixture approaches each limit, in response to the velocity, position and limit signals; detecting circuits for detecting a plurality of predetermined operational faults of the apparatus; an emergency stop circuit for terminating operation of the apparatus upon detection of some of the operation faults; a dynamic brake for braking the servo motor to stop movement of the fixture in response to the emergency stop circuit; and a stop circuit for controlling the motor to stop movement of the fixture upon detection of other operation faults.

Claims

1. A muscle exercise and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

servo motor means coupled to the fixture means;

sensing means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means;

closed loop servo means for controlling said motor means in response to said load signal and said velocity signal to regulate the velocity of said fixture means;

limit means for preventing movement of said fixture means past at least one set limit;

storage means for storing a limit signal corresponding to each said limit; and

limit setting means for enabling said storage means to store the respective limit upon movement of said fixture means to each said limit.

2. A muscle exercise and rehabilitation apparatus according to claim 1;

further including position sensing means for producing a position signal corresponding to the position of said fixture means; and

wherein said storage means stores said position signal as said limit signal, upon enablement by said limit setting means.

3. A muscle exercise and rehabilitation apparatus according to claim 2;

wherein said limit means prevents movement of said fixture means past a first limit in a first direction and a second limit in a second, opposite direction; and

said storage means includes a first sample and hold circuit for storing said position signal corresponding to said first limit and a second sample and hold circuit for storing said position signal corresponding to said second limit, upon enablement by said limit setting means.

4. A muscle exercise and rehabilitation apparatus according to claim 3;

wherein said limit setting means includes first actuation means for enabling said first sample and hold circuit to store said position signal when said fixture means is moved to said first limit and second actuation means for enabling said second sample and hold circuit to store said position signal when said fixture means is moved to said second limit.

5. A muscle exercise and rehabilitation apparatus according to claim 4;

further including mode switch means for setting a mode of operation of said apparatus, said mode switch means being movable to a set-up position, and wherein said first and second actuation means are enabled in response to movement of said mode switch means to said set-up position.

6. A muscle exercise and rehabilitation apparatus according to claim 2;

wherein said storage means further includes limit reducing means for reducing the level of the position signal corresponding to each said limit stored in said storage means.

7. A muscle exercise and rehabilitation apparatus according to claim 6;

wherein said limit reducing means includes potentiometer means connected to an output of said storage means.

8. A muscle exercise and rehabilitation apparatus according to claim 1;

wherein said closed loop servo means includes servo amplifier means for controlling operation of said servo motor means; and

further including set-up means for reducing current supplied to said servo amplifier means when setting said limits.

9. A muscle exercise and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

servo motor means coupled to the fixture means;

sensing means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means;

closed loop servo means for controlling said motor means in response to said load signal and said velocity signal to regulate the velocity of said fixture means;

limit means for preventing movement of said fixture means past at least one set limit;

storage means for storing a limit signal corresponding to each said limit;

position sensing means for producing a position signal corresponding to the position of said fixture means; and

deceleration means for slowing down movement of said fixture means as said fixture means approaches each said limit, in response to said velocity signal, said position signal and said limit signal.

10. A muscle exercise and rehabilitation apparatus according to claim 9;

wherein said closed loop servo means includes servo amplifier means for controlling operation of said servo motor means, and said limit means includes position comparator means for comparing the limit signal corresponding to each limit stored in said storage means with the position signal from said position sensing means corresponding to the actual position of said fixture means, and for controlling said servo amplifier means to prevent movement of said fixture means past each said limit in response thereto.

11. A muscle exercise and rehabilitation apparatus according to claim 10;

wherein said closed loop servo means includes velocity comparator means for comparing the velocity signal with said load signal and for controlling said servo amplifier means in response thereto; and

said position comparator prevents said load signal being supplied to said velocity comparator means when said fixture means is moved to each said limit.

12. A muscle exercise and rehabilitation apparatus according to claim 9;

wherein said closed loop servo means includes servo amplifier means for controlling operation of said servo motor means, velocity setting means for setting a maximum velocity of said fixture means in a first direction and a second, opposite direction, velocity comparator means for comparing the velocity signal with said load signal and for controlling said servo amplifier in response thereto, and velocity regulator means for regulating said load signal in response to said velocity setting means; and

said deceleration means controls said velocity regulator means to slow down movement of said fixture means as said fixture means approaches each said limit.

13. A muscle exercise and rehabilitation apparatus according to claim 9;

wherein said deceleration means includes first comparator means for producing an output signal in response to said velocity signal and said position signal, and second comparator means for comparing said output signal from said first comparator means with the limit signal stored in said storage means to produce a control signal which is supplied to said closed loop servo means to slow down movement of said fixture means as said fixture means approaches each said limit.

14. A muscle exercise and rehabilitation apparatus according to claim 13;

wherein said storage means includes a first storage circuit for storing said position signal corresponding to a first limit as a first limit signal, and a second storage circuit for storing said position signal corresponding to a second limit as a second limit signal, upon enablement by said limit setting means, and said second comparator means includes a first comparator circuit for comparing said output signal with said first limit signal and supplying a first control signal in response thereto to said closed loop servo means to control the latter to slow down movement of said fixture means as said fixture means approaches said first limit and a second comparator circuit for comparing said output signal with said second limit signal and supplying a second control signal in response thereto to said closed loop velocity servo means to control the latter to slow down movement of said fixture means as said fixture means approaches said second limit.

15. A muscle exercise and rehabilitation apparatus according to claim 14;

wherein said closed loop servo means includes servo amplifier means for controlling operation of said servo motor means, velocity setting means for setting a maximum velocity of said fixture means in a first direction and a second, opposite direction, velocity comparator means for comparing the velocity signal with said load signal and for controlling said servo amplifier means in response thereto, and velocity regulator means for regulating said load signal in response to said velocity setting means; and

said first and second comparator circuits supply said first and second control signals to said velocity regulator means to control the latter to slow down movement of said fixture means as said fixture means approaches each said limit.

16. A muscle exercise and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

servo motor means coupled to the fixture means;

sensing means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means;

closed loop servo means for controlling said motor means in response to said load signal and said velocity signal to regulate the velocity of said fixture means, said closed loop servo means including servo amplifier means for controlling operation of said servo motor means, velocity comparator means for comparing the velocity signal with said load signal and for controlling said servo amplifier in response thereto, and switch means for supplying said load signal to said velocity comparator means; and

mode switch means for controlling said switch means in an isometric mode to prevent said load signal being supplied to said velocity comparator means, whereby said fixture means is prevented from moving.

17. A muscle exercise and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

servo motor means coupled to the fixture means;

sensing means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means;

closed loop servo means for controlling said motor means to drive said fixture means in an oscillation mode at a constant velocity in response to said load signal and said velocity signal to regulate the velocity of said fixture means;

limit means for preventing movement of said fixture means past set limits in opposite directions; and

pause means for controlling said closed loop velocity servo feedback means to cause said fixture means to pause at each said limit for a predetermined amount of time.

18. A muscle exercise and rehabilitation apparatus according to claim 17;

wherein said closed loop servo means includes servo amplifier means for controlling operation of said servo motor means, velocity comparator means for comparing the velocity signal with said load signal and for controlling said servo amplifier in response thereto, velocity setting means for setting a maximum velocity of said fixture means in a first direction and a second, opposite direction, velocity regulator means for regulating said load signal in response to said velocity setting means, and passive direction means for supplying a passive direction signal to said velocity regulator means to control the latter to change the polarity of said load signal supplied to said velocity comparator means when said fixture means reaches each said limit to enable said fixture means to move in an opposite direction; and

said pause means delays supplying said passive direction signal to said velocity regulator means for a predetermined amount of time to cause said fixture means to pause at each said limit for said predetermined amount of time.

19. A muscle exercise and rehabilitation apparatus according to claim 17;

wherein said pause means includes adjustment means for varying said predetermined amount of time.

20. A muscle exercise and rehabilitation apparatus according to claim 19;

wherein said adjustment means includes a potentiometer.

21. A muscle exercise and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

servo motor means having an output shaft coupled to the fixture means;

sensing means effectively coupled between said output shaft and said fixture means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means; and

closed loop servo means for controlling said motor means in response to said load signal and said velocity signal to regulate the velocity of said fixture means.

22. A muscle exercise and rehabilitation apparatus according to claim 21;

wherein said sensing means includes a sensing tube effectively coupled between said output shaft and said fixture means, and strain gauge means mounted on said sensing tube for sensing the force applied to the fixture means and for producing said load signal corresponding thereto.

23. A muscle exercise and rehabilitation apparatus according to claim 22;

further including a rotatable shaft to which said fixture means is fixed, mounted in said apparatus, and a flange fixed to one end of said rotatable shaft; and

wherein said sensing tube includes a central tube positioned on said rotatable shaft with said strain gauge means mounted on said central tube, a first flange fixed at one end of said central tube and rotatably fixed with said output shaft and a second flange fixed at an opposite end of said central tube and rotatably fixed with said flange on said rotatable shaft, to thereby effectively couple said sensing means between said output shaft and said fixture means.

24. A muscle exercise and rehabilitation apparatus according to claim 23;

wherein said rotatable shaft is formed with a first section having a first diameter and a second section having a second larger diameter, with said second section being in abutting relation with a housing of said rotatable shaft to limit axial movement of said rotatable shaft; and

said central tube is positioned around said second section to prevent undue axial tightening forces from being placed on said central shaft and the strain gauge means.

25. A muscle exercise and rehabilitation apparatus according to claim 22;

further including wire means for supplying said load signal from said sensing means to said closed loop servo means, and take-up means for preventing entanglement of said wire means during movement of said fixture means.

26. A muscle exercise and rehabilitation apparatus according to claim 25;

wherein said take-up means includes drive gear means mounted for rotation with said sensing tube, driven gear means in meshing engagement with said drive gear means, and a first pulley rotatably fixed with said driven gear means, with said wire means being wrapped about said sensing tube and said first pulley for preventing entanglement of said wire means during movement of said fixture means.

27. A muscle exercise and rehabilitation apparatus according to claim 26;

wherein said take-up means further includes a second pulley mounted on said sensing tube for rotation therewith and rotatably fixed with said drive gear, said wire means from said strain gauge means being wrapped about said second pulley and then about said first pulley;

said first pulley and said driven gear being mounted on a rotatable shaft; and

said first pulley having an aperture through which said wire means extends from said first pulley and is wrapped about said rotatable shaft.

28. A muscle exercise and rehabilitation apparatus according to claim 26;

further including position detecting means for producing a position signal corresponding to the position of said fixture means, said position sensing means including a position gear in meshing engagement with said drive gear, and position sensor means connected with said position gear for determining the position of said fixture means.

29. A muscle exercise and rehabilitation apparatus according to claim 22;

further including a rotatable shaft to which said fixture means is fixed, mounted in said apparatus, said rotatable shaft including a flange fixed to one end thereof and at least one end thereof being tapered and having first securing means thereat; and

wherein said sensing tube is positioned on said rotatable shaft and rotatably fixed with said flange and said output shaft, to thereby effectively coupled said sensing means between said output shaft and said fixture means, and said fixture means includes a tapered bore having at least one flat surface through which each mating tapered end of said rotatable shaft can extend; and

further including second securing means for engaging with said first securing means when said fixture means is positioned on said rotatable shaft to fixedly retain said fixture means on said rotatable shaft in a wedge-like manner so as to substantially reduce backlash.

30. A muscle exercise and rehabilitation apparatus according to claim 29;

wherein said first securing means includes a screw-threaded bore in at least one end of said rotatable shaft; and

said second securing means includes bolt means engageable with an end face of said fixture means and adapted to be screw-threadedly engaged in one said screw-threaded bore.

31. A muscle exercise and rehabilitation apparatus according to claim 22;

further including plate means rotatably fixed with said output shaft, said plate means including a projection, and stop means mounted to said apparatus and engageable with said projection to prevent rotation of said output shaft more than 360 degrees.

32. A muscle exercise and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

servo motor means coupled to the fixture means;

sensing means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means;

closed loop servo means for controlling said motor means in response to said load signal and said velocity signal to regulate the velocity of said fixture means;

detection means for detecting at least one predetermined operational fault of said apparatus;

emergency stop means for terminating operation of said apparatus upon detection of at least one said operation fault; and

brake means for braking said servo motor means to stop movement of said fixture means in response to said emergency stop means.

33. A muscle exercise and rehabilitation apparatus according to claim 32;

further including position sensing means for producing a position signal corresponding to the position of said fixture means; and

wherein said detection means includes speed detecting loss means for detecting an operational fault of said speed detecting means, said speed detecting loss means including rate means for producing a speed signal in response to the rate of change of said position signal, and comparator means for comparing said speed signal and said velocity signal and for supplying an error signal to said emergency stop means when said speed signal and said velocity signal differ by a predetermined amount.

34. A muscle exercise and rehabilitation apparatus according to claim 32;

further including limit means for preventing movement of said fixture means past at least one set limit; and

wherein said detection means includes over limit means for detecting when said fixture means has moved past said at least one set limit and for supplying an error signal to said emergency stop means in response thereto.

35. A muscle exercise and rehabilitation apparatus according to claim 34;

further including position sensing means for producing a position signal corresponding to the position of said fixture means, and storage means for storing a limit signal corresponding to each said limit; and

wherein said over limit means includes comparator means for comparing said position signal with said limit signal and for supplying an error signal to said emergency stop means when said position signal is greater than said limit signal.

36. A muscle exercise and rehabilitation apparatus according to claim 32;

further including velocity setting means for controlling said closed loop velocity servo feedback means to prevent movement of said fixture means greater than a preset maximum velocity; and

wherein said detection means includes over speed sensing means for detecting if said fixture means is moving at a speed greater than said preset maximum velocity, in response to said velocity setting means and said speed detecting means, and for supplying an error signal to said emergency stop means when the speed of said fixture means is greater than said preset maximum velocity.

37. A muscle exercise and rehabilitation apparatus according to claim 32;

wherein said detection means includes power loss means for detecting if there is a power loss from a power supply of said apparatus and for supplying an error signal to said emergency stop means when such a power loss is detected thereby.

38. A muscle exercise and rehabilitation apparatus according to claim 32;

further including limit means for preventing movement of said fixture means past at least one set limit, actuation means for setting said at least one set limit, and mode switch means for setting a mode of operation of said apparatus, said mode switch means being movable to a set-up position to enable said actuation means for setting said at least one set limit, and set-up means for reducing current to said servo motor means when said mode switch means is moved to said set-up position; and

wherein said detection means includes current detection means for detecting if said current supplied to said servo motor means during the set-up mode is greater than a predetermined value and for supplying an error signal to said emergency stop means in response thereto.

39. A muscle exercise and rehabilitation apparatus according to claim 32;

wherein said emergency stop means shuts off all power to said servo motor means upon detection of at least one said operation fault.

40. A muscle exercise and rehabilitation apparatus according to claim 32;

wherein said brake means includes resistive means connected across said servo motor means in response to a signal from said emergency stop means for braking said servo motor means to stop movement of said fixture means in response to said emergency stop means.

41. A muscle exercise and rehabilitation apparatus according to claim 32;

further including indicator means for indicating when at least one predetermined operational fault of said apparatus is detected.

42. A muscle exercise and rehabilitation apparatus according to claim 41;

wherein said indicator means includes an indicator light for each predetermined operational fault.

43. A muscle exercise and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

servo motor means coupled to the fixture means;

sensing means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means;

closed loop servo means for controlling said motor means in response to said load signal and said velocity signal to regulate the velocity of said fixture means;

detection means for detecting at least one predetermined operational fault of said apparatus; and

stop means for controlling said servo motor means to stop movement of said fixture means upon detection of at least one said operation fault.

44. A muscle exercise and rehabilitation apparatus according to claim 43, wherein said detection means includes load sensing loss means for detecting an operational fault of said sensing means and for supplying an error signal to said stop means in response thereto.

45. A muscle exercise and rehabilitation apparatus according to claim 43;

further including first position sensing means for producing a first position signal corresponding to the position of said fixture means and second, redundant position sensing means for producing a second position signal corresponding to the position of said fixture means; and

wherein said detection means includes position loss means for supplying an error signal to said stop means when said first and second position signals are not equal.

46. A muscle exercise and rehabilitation apparatus according to claim 43;

wherein said detection means includes under voltage means for detecting if voltage from a power supply of said apparatus is less than a predetermined voltage, and for supplying an error signal to said stop means in response thereto.

47. A muscle exercise and rehabilitation apparatus according to claim 43;

further including comfort stop actuation means; and

said detection means includes means for supplying an error signal to said stop means upon actuation of said comfort stop actuation means.

48. An muscle exercise and rehabilitation apparatus according to claim 43;

further including limit means for preventing movement of said fixture means past at least one set limit; and

wherein said detection means includes change in limit means for detecting when said at least one set limit has changed by a predetermined amount and for supplying an error signal to said stop means in response thereto.

49. A muscle exercise and rehabilitation apparatus according to claim 48;

further including first storage means for storing a first limit signal corresponding to each said limit and second, redundant storage means for storing a second limit signal corresponding to each said limit; and

wherein said change in limit means includes comparator means for comparing first and second limit signals and for supplying an error signal to said stop means when said first and second limits signals differ by a predetermined amount.

50. A muscle exercise and rehabilitation apparatus according to claim 43;

wherein said closed loop servo means includes servo amplifier means for controlling operation of said servo motor means, said servo amplifier means including at least one storage element for storing residual power, and said stop means shuts off all power to said servo motor means upon detection of at least one said operation fault, and controls said servo amplifier means to stop movement of said fixture means with said residual power.

51. A muscle exercise and rehabilitation apparatus according to claim 50;

wherein said storage element includes at least one capacitive element.

52. A muscle evaluation and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

servo motor means coupled to the fixture means;

sensing means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means;

closed loop servo means for controlling said motor means in response to said load signal and said velocity signal to regulate the velocity of said fixture means;

limit means for preventing movement of said fixture means past at least one set limit;

storage means for storing a limit signal corresponding to each said limit; and

limit setting means for enabling said storage means to store the respective limit upon movement of said fixture means to each said limit.

53. A muscle exercise and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

servo motor means coupled to the fixture means;

sensing means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means;

closed loop servo means for controlling said motor means in response to said load signal and said velocity signal to regulate the velocity of said fixture means;

a rotatable shaft to which said fixture means is fixed, mounted in said apparatus, at least one end of said rotatable shaft being tapered and having first securing means thereat;

said fixture means includes a wedge-shaped tapered bore through which each tapered end of said rotatable shaft can extend; and

second securing means for engaging with said first securing means when said fixture means is positioned on one end of said rotatable shaft to fixedly retain said fixture means on said rotatable shaft in a wedge-like manner so as to substantially reduce backlash.

54. A muscle exercise and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

servo motor means coupled to the fixture means;

sensing means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means;

closed loop servo means for controlling said motor means in response to said load signal and said velocity signal to regulate the velocity of said fixture means;

at least one manually operated comfort stop actuator for stopping movement of said fixture means; and

stop means for controlling said servo motor means to stop movement of said fixture means in response to said at least one manually operated comfort stop actuator.

55. A muscle exercise and rehabilitation apparatus according to claim 54;

wherein there are two manually operated comfort stop actuators, one positioned on said apparatus and the other connected to said apparatus by electrical wires and adapted to be held by a user of said apparatus during operation of said apparatus.

56. A muscle exercise and rehabilitation apparatus comprising:

movable fixture means against which a force can be applied;

a rotatable shaft to which said fixture means is fixed, mounted in said apparatus, at least one end of said rotatable shaft being tapered and having first securing means thereat;

said fixture means includes a wedge-shaped tapered bore through which each tapered end of said rotatable shaft can extend;

second securing means for engaging with said first securing means when said fixture means is positioned on one end of said rotatable shaft to fixedly retain said fixture means on said rotatable shaft in a wedge-like manner so as to substantially reduce backlash;

servo motor means having an output shaft coupled to the fixture means;

sensing means effectively coupled between said output shaft and said fixture means for sensing the force applied to the fixture means and for producing a load signal corresponding thereto;

speed detecting means for producing a velocity signal corresponding to the speed of the fixture means;

closed loop servo means for controlling said motor means in response to said load signal and said velocity signal to regulate the velocity of said fixture means, said closed loop servo means including servo amplifier means for controlling operation of said servo motor means, velocity comparator means for comparing the velocity signal with said load signal and for controlling said servo amplifier in response thereto, and switch means for supplying said load signal to said velocity comparator means;

limit means for preventing movement of said fixture means past at least one set limit;

storage means for storing a limit signal corresponding to each said limit;

limit setting means for enabling said storage means to store the respective limit upon movement of said fixture means to each said limit;

position sensing means for producing a position signal corresponding to the position of said fixture means;

deceleration means for slowing down movement of said fixture means as said fixture means approaches each said limit, in response to said velocity signal, said position signal and said limit signal;

pause means for controlling said closed loop servo means to cause said fixture means to pause at each said limit for a predetermined amount of time;

mode switch means for controlling said switch means in an isometric mode to prevent said load signal being supplied to said velocity comparator means, whereby said fixture means is prevented from moving, regardless of the force applied thereto, an isokinetic mode in which said fixture means is caused to move with a regulated velocity and an oscillation mode in which said fixture means is caused to oscillate at a constant velocity;

detection means for detecting at least one predetermined operational fault of said apparatus;

at least one manually operated comfort stop actuator for stopping movement of said fixture means;

emergency stop means for terminating operation of said apparatus upon detection of at least one of a predetermined set of said operation faults;

brake means for braking said servo motor means to stop movement of said fixture means in response to said emergency stop means; and

stop means for controlling said servo motor means to stop movement of said fixture means upon detection of at least one operation fault and in response to said comfort stop actuator.