Control of multiple arms with rolling constraints

IEEE Trans. Robot. Automat.

1997

Self Cite

106

When two or more arms are used to manipulate a large object, it is preferable not to have a rigid grasp in order to gain more dexterity in manipulation. It may therefore be necessary to control contact motion between the object and the effector(s) on one or more arms. This paper addresses the dynamic control of two arms cooperatively manipulating a large object with rolling contacts. In the framework presented here, the motion of the object as well as the loci of the contact point either on the surface of each effector or on the object can be directly controlled. The velocity and acceleration equations for three-dimensional rolling contacts are derived in order to obtain a dynamic model of the system. A nonlinear feedback control algorithm that decouples and linearizes the system is developed. This is used to demonstrate the control of rolling motion along each arm and the adaptation of grasps to varying loads. KeywordsDextrous manipulation, grasping, rolling contact, two-arm manipulation. Disciplines Engineering | Mechanical Engineering CommentsSuggested Citation: Sarkar, N., X. Yun and V. Kumar (1997 Abstract-When two or more arms are used to manipulate a large object, it is preferable not to have a rigid grasp in order to gain more dexterity in manipulation. It may therefore be necessary to control contact motion between the object and the effector(s) on one or more arms. This paper addresses the dynamic control of two arms cooperatively manipulating a large object with rolling contacts. In the framework presented here, the motion of the object as well as the loci of the contact point either on the surface of each effector or on the object can be directly controlled. The velocity and acceleration equations for three-dimensional rolling contacts are derived in order to obtain a dynamic model of the system. A nonlinear feedback control algorithm that decouples and linearizes the system is developed. This is used to demonstrate the control of rolling motion along each arm and the adaptation of grasps to varying loads.

Section: Previous Workmentioning

confidence: 99%

Section: A State Space Representationmentioning

confidence: 99%

See 1 more Smart Citation

Dynamic control of 3-D rolling contacts in two-arm manipulation

Sarkar

IEEE Trans. Robot. Automat.

1997

Self Cite

106

“…Although it has been shown that a nonholonomic system cannot be feedback-stabilized to a single equilibrium point by a smooth feedback, the system is small-time locally controllable (Bloch et al 1992). Additionally, even though such a system is not input-state linearizable, the input-output linearization is still possible with properly chosen output equations (Yun et al 1992). …”

Section: Previous Workmentioning

confidence: 99%

Control of Contact Interactions with Acatastatic Nonholonomic Constraints

Sarkar

The International Journal of Robotics Research

1997

A robot arm performs many tasks by interacting with objects or other robots in the environment. It is important for the robot arm to be able to exhibit controlled interactions with the objects and other robots. The contact motion between the robot arm and an object can be rolling, sliding, or separation. In this article, we address the problem of maintaining rolling contact between the robot arm and an external moving object. We assume that a nominal model of the motion of the moving object is available. The dynamic system that characterizes the motion of the robot arm and the moving object in this case is acatastatic and nonholonomic. We have designed a nonlinear feedback for the control of such a system that successfully maintains rolling contact. Simulation results are presented to demonstrate the effectiveness of the system.

“…Therefore i may be chosen to consist of 3-dimensional po and two other independent position variables. Since the objective is to control the rolling contact, we choose two contact configuration variables [52]. The point of contact on the zth palm is described by the contact coordinate d, which is the arc-length along the palm as shown in Figure 2.…”

Section: Exanlple With Two Planar 3-r Illa~lipulatorsmentioning

confidence: 99%

Control of rolling contacts in multi-arm manipulation

Paljug

IEEE Trans. Robot. Automat.

1994

Self Cite

112

When multiple arms are used to manipulate a large object, it is beneficial and sometimes necessary to maintain and control contacts between the object and the effector (the contacting surface of an arm) through force closure. Rolling and/or sliding can occur at these contacts, and the system is characterized by holonomic as well as nonholonomic (including unilateral) constraints. In this paper, the control of planar rolling contacts is investigated. Multi-arm manipulation systems are typically redundant. In our approach, a minimal set of inputs is employed to control the trajectory of the system while the surplus inputs control the contact condition. The trajectory includes the gross motion of the object as well as the rolling motion at the contacts. A nonlinear feedback scheme for simultaneous control of motion as well as contact conditions is presented. A new algorithm which adapts a two-effector grasp with rolling contacts to external loads and the trajectory is developed. Simulations and experimental results are used to illustrate the salient features in control and planning. ABSTRACTWhen multiple arms are used to manipulate a large object, it is beneficial and sometimes necessary to maintain and control contacts between the object and the effector (the coiltactiilg surface of an arm) through force closure. Rolling and/or sliding can occur at these contacts, and the system is characterized by holonomic as well as nonholonomic (including unilateral) constraints. In this paper, the control of planar rolling contacts is investigated. Multi-arm nlanipulation systems are typically redundant. In our approach, a minimal set of inputs is employed to control the trajectory of the systeln while the surplus inputs control the contact condition. The trajectory includes the gross motion of the object as well as the rolling motion at the contacts. A nonlinear feedback scheme for simultaneous control of motion as well as contact conditions is presented. A new algorithm which adapts a two-effector grasp with rolling contacts to external loads and the trajectory is developed. Simulations and esperimeiltal results are used to illustrate the salient features in control and pla.nning.