Electricity: motive power systems – Plural diverse motor controls – Running-speed control
Patent
1988-04-28
1990-12-18
Ro, Bentsu
Electricity: motive power systems
Plural diverse motor controls
Running-speed control
318139, 318375, H02P 308
Patent
active
049788990
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to controls for electric or fluid actuators, and to conveyances propelled by electric or fluid actuators. More particularly, the present invention relates to dynamically braking conveyances, and to controlling the turns of conveyances that are steered by separately controlling the speeds of the wheels.
2. Description of the Related Art
Conveyances of various types, for transporting people, for material handling, and for propelling self-propelled machinery, have requirements for extremely high maneuverability.
One way to obtain extremely high maneuverability is to separately and variably control the speed and direction of rotation of left and right wheels or other propulsion elements. When the wheels are moving at the same speed, but in opposite directions, the conveyance pivots in a fixed location, giving the ultimate in maneuverability.
A propulsion system using electric or hydraulic motors can provide flexibility of control, but precision of control has been lacking in prior art designs.
Further, achieving high maneuverability by separately controlling the velocity and direction of rotation of the wheels, or other traction elements, may make a conveyance difficult to control, or even dangerous.
For instance, it may be desirable to have the ability to make pivot turns with some conveyances, but it might be dangerous to attempt to make a pivotal turn at full speed.
But, if the rate of change of speed of the individual wheels is limited, then the machine may be sluggish in acceleration, and may be dangerously slow in deceleration.
The problem of controllability is particularly acute in wheelchairs, and the discussion that follows centers on electricallypropelled wheelchairs.
Typically, separate D.C. electric motors have been connected to left and right wheels of a wheelchair by chains or belts, and by friction rollers that have separately engaged the rubber tires of the wheels.
D.C. motors provide both directions of rotation by changing polarity of the driving voltage, and produce rotational speeds that are dependent upon both the driving voltage and the torque required of them.
Manually actuated controls have been used that separately and variably supply electric power from a battery to left and right motors to make changes in speed, and to make turns, including pivot turns.
One popular type of manual control includes a control lever that is moved forward in accordance with a desired speed forward, that is moved rearward in accordance with a desired speed in reverse, that is moved both forward and to one side to make a turn while moving forward, and that is moved directly to one side to make a pivot turn.
One problem with prior art designs is that control of speed and direction has been uncertain because of the lack of dynamic braking. For instance, when the control lever has been positioned to make a left turn by reducing the electrical power to the left motor, inertia of the wheelchair and occupant has driven the left motor through the drive train that connects the left motor to the left wheel, and the wheelchair has not turned at the desired radius.
A second problem is that it has been necessary to engage and disengage the mechanical drive that connects the motors to their respective wheels, in order to manually propel electric wheelchairs. This has increased design complexity and manufacturing costs.
Commonly a driving connection between the motors and the wheels has been accomplished by using drive rollers that engage the tires. Engagement and disengagement of this driving connection has been accomplished by movement of the motors and mechanical drives, and by resultant movement of the drive rollers into, and away from, engagement with the tires, or by belt tighteners.
A third problem is that disengagement of the mechanical drive has left the wheelchair in a dangerous run-away condition in situations where someone has inadvertently forgotten to set the parking brake. That is, prior art designs have provided neither an automa
REFERENCES:
patent: 3260912 (1966-07-01), Gregory
patent: 3582747 (1971-06-01), Kearns
patent: 3934181 (1976-01-01), Rosenthal
patent: 4323829 (1982-04-01), Witney et al.
patent: 4361788 (1982-11-01), Melocik
patent: 4415049 (1983-11-01), Wereb
patent: 4500818 (1985-02-01), Konrad et al.
patent: 4511825 (1985-04-01), Klimo
patent: 4604557 (1986-08-01), Cowles
patent: 4667136 (1987-05-01), Bell
Lautzenhiser John L.
Lautzenhiser Lloyd L.
Miller Wendell E.
Ro Bentsu
LandOfFree
Conveyance with electronic control for motors does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Conveyance with electronic control for motors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Conveyance with electronic control for motors will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1427773