Intelligent commutation pulse detection system to control electric D.C. motors used with automobile accessories

• US 5,497,326 A
• Filed: 08/03/1994
• Issued: 03/05/1996
• Est. Priority Date: 08/03/1994
• Status: Expired due to Term

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Cherry Corporation (ZF Electronics Corp.)
• Inventors: Berland, Kerry, Kaul, Jeff, Budniak, Mitchell
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/285,310
• Time in Patent Office: 580 Days
• Field of Search: 364/424.05, 364/424.01, 364/483, 364/571.02, 364/155, 364/176, 307/9.1, 307/10.1, 296/65.1, 318/467, 318/468, 318/470, 318/476, 318/478, 318/264, 318/265, 318/266, 49/26, 49/28
• US Class Current: 701/36
• CPC Class Codes: B60N 2/0244 with logic circuits
• CPC Class Codes: G05B 19/4062 Monitoring servoloop, e.g. overload of servomotor, loss of feedback or reference
• CPC Class Codes: G05B 2219/34215 Microprocessor
• CPC Class Codes: G05B 2219/37169 Derive incremental pulse from motor current deviation
• CPC Class Codes: G05B 2219/37282 Current transformator
• CPC Class Codes: G05B 2219/42288 Limit, stop drive current if axis obstructed, blocked, force against stop
• CPC Class Codes: G05B 2219/42294 Software monitoring of time delay of feedback pulses, feedback failure
• CPC Class Codes: G05B 2219/42322 Emit dummy pulses, detect loss of pulses, feedback failure, wire brake, short
• CPC Class Codes: G05B 2219/45022 Auto seat, dentist chair, roll wheel chair
• CPC Class Codes: H02P 7/0094 wherein the position is detected using the ripple of the current caused by the commutator

Abstract

A control system for use with a bidirectional motor connected to a motorized vehicle accessory to move the accessory a distance from a first position to a second position. The control system includes a detector responsive to control signals emitted from the motor during rotation, where the control signals indicate the amount of motor rotation. The control system also includes a memory that stores information used to represent the position of the accessory. Additionally, this control system includes a controller responsive to the memory and the detector. The controller provides an output signal to operate the motor based on the distance between a first position and a second position of the accessory as well as control signals that indicate the amount of motor rotation. The controller includes an adjustment routine that determines a correction factor that is applied to the output signal to compensate for inaccuracies in control signal detection.

Claims

1. A control system for use with a bidirectional motor connected to a motorized vehicle accessory to move said accessory a distance from a first position to a second position, said control system comprising:

(a) a detector responsive to control signals emitted by said motor during rotation, said control signals indicative of an amount of rotation of said motor;

(b) a memory; and

(c) a controller responsive to said memory and said detector, and providing an output signal to said motor for operation thereof as a function of a relationship between said distance and said control signals, said controller further including;

a routine for applying an adjustment factor to said output signal to correct for inaccuracies in detection of said control signals.

2. The control system of claim 1, wherein said memory includes information indicative of said first position.

3. The control system of claim 2, wherein said controller includes a microprocessor.

4. The control system of claim 2, wherein said motor includes a fixed number of poles;

said memory includes data indicative of said second position, and a position recall routine responsive to said data from said memory for rotating said motor through a number of motor poles to move said accessory to said second position; and

wherein said routine evaluates said control signals to determine when a commutation pulse may have been missed and when an extra commutation pulse may have been detected for reducing error accumulation in a position of said accessory stored in said memory.

5. The control system of claim 4, wherein said memory and said controller comprises a microprocessor.

6. The control system of claim 1, wherein said detector comprises a current detecting resistor in series with said motor and an amplifier electrically connected to said current detecting resistor.

7. A control system for engaging a bidirectional motor to manipulate an accessory over a bidirectional travel path in a motorized vehicle, comprising:

(a) a sensor for detecting a commutation waveform corresponding to current passing through said motor;

(b) a comparator for deriving a digital pulse train from said commutation waveform;

(c) a memory for receiving and storing data representative of said commutation waveform and said digital pulse train, said memory including a programmed feature; and

(d) a controller responsive to said data and said feature, said controller providing an output signal to control said motor.

8. The control system of claim 7, wherein said feature includes an obstruction detection routine for stopping said accessory by controlling said output signal to said motor when an unexpected load on said motor is detected by said routine.

9. The control system of claim 8, wherein said feature includes a motor slow down routine to slow down said motor when said accessory'"'"'s position approaches an end of said travel path, thereby providing increased obstruction detection sensitivity.

10. The control system of claim 7, wherein said feature includes a soft stop routine to slow down said motor when said accessory approaches an end of said travel path and to gently stop said accessory at said end of said travel path, thereby reducing wear on said motor.

11. The control system of claim 7, wherein said feature includes a missing pulse routine and a double pulse routine responsive to said commutation waveform for reducing error accumulation over time by correcting a position of said accessory stored in said memory.

12. The control system of claim 7, wherein said accessory is selected from the group consisting of a window, a mirror, a seat, and a sunroof.

13. The control system of claim 7, wherein said comparator comprises a device for toggling a digital output when the first derivative of said commutation waveform changes from a positive to a negative value, and a noise reduction device to remove noise from said commutation waveform.

14. The control system of claim 7, wherein said system includes a plurality of motors and said output signal is modified by a motor cross-talk limiting system coupled to said sensor for reducing inrush current surges generated by other motors in the control system when said other motors start and stop.

15. A control system for engaging a bidirectional motor to manipulate an accessory over a bidirectional travel path in a motorized vehicle, comprising:

(a) a sensor for detecting a commutation waveform corresponding to current passing through said motor;

(b) a detector for generating a digital pulse train from said motor, said detector including a device for sensing pole crossings located near at least one pole of said motor;

(c) a memory for receiving and storing data representative of said commutation waveform and said digital pulse train, said memory including a programmed feature; and

(d) a controller responsive to said data and said feature, said controller providing an output signal to control said motor.

16. The control system of claim 15, wherein said detector includes one of an optical sensor and a hall effect sensor.

17. A control system for controlling a motorized vehicle accessory including at least one motor operable from a d.c. power source for adjusting said accessory, and a memory for storing a plurality of positions of said accessory, the control system comprising:

(a) a sensor for detecting current supplied from said d.c. power source to said motor;

(b) a generator for generating a signal indicative of a position of said accessory from current fluctuations in a supply line from d.c. power source to said motor during an adjustment in said position of said accessory; and

(c) a controller including a first routine for monitoring said signal for conditions indicative of an obstruction in a path of said accessory based upon a rate of change of said current fluctuations relative to said position and a second routing to send an output signal to said motor to stop said accessory thereby providing an automatic safety feature.

18. The control system of claim 17, wherein said controller includes a routine that monitors said signal for conditions that indicate said accessory is close to an end of a traversal path and then sends an output signal to slow down said motor to gently stop said accessory.

19. A method of controlling an accessory of a motorized vehicle including at least one motor operable from a d.c. power source for adjusting a position of said accessory, a memory for storing a plurality of positions of said accessory, and a microcomputer based electronic controller, comprising the steps of:

(a) sensing current supplied from said d.c. power source to said motor;

(b) generating a signal indicative of the position of said accessory from current fluctuations in a supply line from said d.c. power source to said motor during an adjustment in the position of said accessory;

(c) measuring said signal to determine a number of commutation pulses that have been missed and a number of double pulses; and

(d) compensating for said number of missing commutation pulses and said number of double pulses to store a corrected data position representing said accessory position into said memory.

20. A method of controlling an accessory of a motorized vehicle including at least one motor operable from a d.c. power source for adjusting a position of said accessory, a memory for storing a plurality of positions of said accessory, and a microcomputer based electronic controller, comprising the steps of:

(a) synchronously sampling current supplied from said d.c. power source to said motor to generate a signal indicative of current fluctuations during an adjustment in the position of said accessory; and

(b) monitoring said signal for conditions that indicate an obstruction is in a traversal path of said accessory to stop said accessory.

21. A system for controlling an accessory of a motorized vehicle including at least one motor operable from a d.c. power source for adjusting a position of said accessory, a memory for storing a plurality of positions of said accessory, and a microcomputer based electronic controller, comprising:

(a) means for sensing current supplied from said d.c. power source to said motor;

(b) means for generating a signal indicative of the position of said accessory from current fluctuations in a supply line from said d.c. power source to said motor during an adjustment in the position of said accessory;

(c) means for measuring said signal to determine a number of commutation pulses that have been missed and a number of double pulses; and

(d) means for compensating for said number of missing commutation pulses and said number of double pulses to store a corrected data position representing said accessory position into said memory.

22. A system for controlling an accessory of a motorized vehicle including at least one motor operable from a d.c. power source for adjusting a position of said accessory, a memory for storing a plurality of positions of said accessory, and a microcomputer based electronic controller, comprising:

(a) means for generating a signal from current fluctuations in a supply line from said d.c. power source to said motor during an adjustment in the position of said accessory; and

(b) means for monitoring said signal for conditions that indicate an obstruction is in a travel path of said accessory to stop said accessory based on comparable portions of said fluctuations.

23. A control system for use with a bidirectional motor connected to a motorized vehicle accessory to move said accessory a distance from a first position to a second position, said control system comprising:

(a) means for detecting control signals emitted by said motor during rotation, said control signals indicative of an amount of rotation of said motor;

(b) a memory including a representative control signal waveform; and

(c) a controller responsive to said memory and said detecting means, and providing an output signal to said motor for operation thereof as a function of a relationship between said distance and said control signals, said controller including;

(i) means for comparing said control signals detected by said detecting means to a running average of said control signals, and

(ii) means for adjusting said output signal to said motor as a function of said comparison made by said comparing means.

24. A control system for use with a bidirectional motor that generates control signals indicative of an amount of rotation of said motor, said bidirectional motor connected to a motorized vehicle accessory to move said accessory a distance from a first position to a second position, said control system comprising:

(a) a detector responsive to said control signals;

(b) a means for synchronously sampling said control signals with the generation thereof; and

(c) a controller responsive to said synchronous sampling means for providing an output signal to said motor for operation thereof as a function of a relationship between said distance and said control signals.

25. The control system of claim 24 wherein said control signals comprise commutation pulse signals.

26. The control system of claim 24 wherein said control signals are output from a sensor located relative to said motor to provide an output indicative of movement thereof.

27. The control system of claim 26 wherein said sensor is an optical sensor.

28. The control system of claim 26 wherein said sensor is a Hall effect sensor.

29. A control system for controlling a motorized vehicle accessory including at least one motor operable from a d.c. power source for adjusting said accessory, and a memory for storing a plurality of positions of said accessory, the control system comprising:

(a) a sensor for detecting current supplied from said d.c. power source to said motor;

(b) a generator for generating a signal indicative of a position of said accessory from current fluctuations in a supply line from said d.c. power source to said motor during an adjustment in said position of said accessory; and

(c) a controller for monitoring said signal for conditions indicative of an obstruction in a path of said accessory based upon a rate of change of said current fluctuations relative to said position and sending a signal to said motor to alter operation thereof upon said indication thereby providing an automatic safety feature.