Position and force control of a vehicle with two or more steerable drive wheels

Conference · Wed Jan 01 04:00:00 EST 1992

OSTI ID:6723787

Reister, D B; Unseren, M A

When a vehicle with two or more steerable drive wheels is traveling in a circle, the motion of the wheels is constrained. The wheel translational velocity divided by the radius to the center of rotation must be the same for all wheels. When the drive wheels are controlled independently using position control, the motion of the wheels may violate the constraints and the wheels may slip. Consequently, substantial errors can occur in the orientation of the vehicle. A vehicle with N drive wheels has (N - 1) constraints and one degree of freedom. We have developed a new approach to the control of a vehicle with N steerable drive wheels. The novel aspect of our approach is the use of force control. To control the vehicle, we have one degree of freedom for the position on the circle and (N - 1) forces that can be used to reduce errors. Recently, Kankaanranta and Koivo developed a control architecture that allows the force and position degrees of freedom to be decoupled. In the work of Kankaanranta and Koivo the force is an exogenous input We have made the force endogenous by defining the force in terms of the errors in satisfying the rigid body kinematic constraints. We have applied the control architecture to the HERMIES-M robot and have measured a dramatic reduction in error (more than a factor of 20) compared to rations without force control.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6723787
• Report Number(s): CONF-930519-2; ON: DE92041301
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420203* -- Engineering-- Handling Equipment & Procedures
COMPUTERIZED CONTROL SYSTEMS
CONTROL SYSTEMS
DEGREES OF FREEDOM
DIFFERENTIAL EQUATIONS
EQUATIONS
EQUATIONS OF MOTION
MOTION
NAVIGATION
ON-LINE CONTROL SYSTEMS
ON-LINE SYSTEMS
PARTIAL DIFFERENTIAL EQUATIONS
ROBOTS
ROTATION
TORQUE
VEHICLES
WHEELS