Self-propelled vehicle

• US 5,213,176 A
• Filed: 12/07/1990
• Issued: 05/25/1993
• Est. Priority Date: 12/08/1989
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takehara, Naoki, Adachi, Kazumi, Akaiwa, Masayasu, Kikuchi, Hiroshi, Oroku, Noriyuki, Takahashi, Isao, Ikeda, Minoru, Suzuki, Takamichi, Hamada, Toyohide
• Primary Examiner(s): Focarino, Margaret A.
• Assistant Examiner(s): MAR, MICHAEL Y
• Application Number:
  US07/624,052
• Time in Patent Office: 900 Days
• Field of Search: 180/168, 180/210, 180/211, 180/212, 180/214
• US Class Current: 180/168
• CPC Class Codes: B60B 19/003 Multidirectional wheels
• CPC Class Codes: B60B 2360/50 Rubbers
• CPC Class Codes: B60B 2900/531 User-friendliness
• CPC Class Codes: B60Y 2200/60 Industrial applications, e.g. pipe inspection vehicles
• CPC Class Codes: B62D 61/06 with only three wheels
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: H01L 21/67724 by means of a cart or a vehicule

Abstract

A self-propelled vehicle capable of all directional movement over a floor surface and adapted to be guided along a path such as a semiconductor processing line. The vehicle is provided with at least three wheels having a construction enabling rotational movement in a rotational plane of the wheel and in a direction orthogonal thereto. When at least four wheels are provided, the vehicle is provided with a suspension mechanism for mounting the wheels and a mechanism for maintaining a parallel relationship of the suspension mechanism and a chassis of the vehicle so that slanting of the vehicle body during travel is avoided. Also, the vehicle is provided with a vibration preventing base interposed between the vehicle and a substance mounting base for controlling the proper vibration frequency of the vibration presenting base to be lower than 1/√2 of the proper vibration frequency of the vehicle.

Claims

1. A self-propelled vehicle comprising:

at least three wheels for driving the vehicle, each wheel including at least one shaft extending in a tangential direction of an outer circumferential surface of the wheel, and roller means rotatable mounted for rotation about the at least one shaft so that the wheel is movable at least in a rotational direction of the wheel and a rotational direction of the roller means;

means for mounting the at least three wheels with respect to a chassis of the vehicle in directions so that the rotary axes of the wheels are in a nonparallel relationship, the chassis having a major rectangular shape with a pair of sides and a minor sides, the major axis being longer than the minor sides, one of the wheels being mounted at the center point of one of the major sides and the two remaining wheels being mounted at opposite ends of the other one of the major sides, and

motor means for driving respective ones of the at least three wheels, and control means for controlling the motor means, the control means including means for detecting a lateral deviation of the vehicle with respect to the travelling direction of the vehicle and an angular deviation of the travelling direction with respect to a guidance target, means for evaluating a predetermined determinant in accordance with the travelling direction of the vehicle together with a desired travelling speed, means for estimating circumferential speeds of the at least three wheels in accordance with the results of evaluating the determinant, and rotational speed means for controlling the rotational speed of the motor means for the at least three wheels in accordance therewith.

2. A vehicle according to claim 1, wherein the control means for the motor means includes amplifier means.

3. A vehicle according to claim 1, wherein the angle formed between the travelling direction of the vehicle and the vehicle is maintained constant, and the predetermined determinant is evaluated with respect to the lateral deviation of the vehicle with respect to the travelling direction.

4. A self-propelled vehicle comprising:

a rectangular chassis having a pair of major sides and a pair of minor sides, the major sides being longer than the minor sides;

three wheels for supporting the chassis on a travelling surface for the vehicle, the three wheels being mounted so that the rotary axes of the wheels are in a nonparallel relationship and arranged so that a rotational plane of one wheel is directed in a direction extending substantially in parallel to the main travelling direction of the vehicle along a guide target formed on the travelling surface, and rotational planes of the remaining two wheels being directed at symmetrical opposite angles with respect to the main travelling direction of the vehicle, one of the wheels being mounted at the center point of one of the major sides and the two remaining wheels being mounted at opposite ends of the other one of the major sides each of the wheels being connected to a respective motor mounted on the chassis for driving a respective wheel, each of the wheels including a plurality of roller lines arranged alternately in a zig-zag form about the outer circumferential surface of the wheel so that rollers of one roller line are overlapped in relation to rollers of another roller line, each of the rollers of a respective roller line being rotatably mounted for rotation about a shaft arranged so as to extend in a tangential direction of an outer circumferential surface of the wheel, and each of the rollers having a barrel shape so that a circumferential surface of one of the rollers of the wheels is always in contact with the travelling surface;

power means provided on the chassis for at least supplying power to the driving motors for the wheels; and

controlling means for controlling each of the driving motors for driving the wheels in accordance with a longitudinal direction travelling speed, a lateral travelling speed and rotational angles speed obtained by a lateral deviation and an angular deviation of the vehicle measured by a sensor mounted on the vehicle for sensing the guide target.

5. A vehicle according to claim 4, wherein the rotational planes of the remaining two wheels are directed respectively in directions of +45°

and -45°

with respect to the main travelling direction of the vehicle.

6. A vehicle according to claim 4, wherein the at least three wheels are arranged on the chassis at an angle such that a line formed by a rotary axis of each wheel passes through a position proximate to and at least one of above and below a center of gravity of the vehicle.

7. A vehicle according to claim 4, wherein the controlling means for the motor means includes amplifier means.

8. A vehicle according to claim 4, further comprising means provided on the vehicle for mounting a substance to be carried by the vehicle, a robot mechanism mounted on the vehicle for handling the substance to be carried by the vehicle, and vibration preventing base means interposed between the vehicle and the substance mounting means for reducing vibration acceleration applied to the substance carried by the vehicle, the vibration preventing base means including vibration frequency means for controlling a vibration frequency of the vibration preventing base means so as to be lower than a vibration frequency of the vehicle.

9. A vehicle according to claim 8, wherein the vibration frequency means controls the vibration frequency of the vibration preventing base means to be lower than 1/√

2 of the vibration frequency of the vehicle.

10. A self-propelled vehicle according to claim 4, wherein each of the wheels is disposed within a boundary of the chassis.