The objective of this research is to develop motion and force control methods for coordinated robots. The robots are assumed to grasp rigidly an object, and the purpose of the cooperating control is to regulate the object motion, the contact force between the object and environment, with which it comes in contact, and the internal force, which does not contribute to the object motion and contact force. The control problem is delined in a system-theoretical framework, where desired trajectories of motion and forces are tracked asymptotically.

In this research, both joint redundant and nonredundant robots are considered. Four motion and force control problems are defined and solved:​ (i) motion and force control of coordinated robots in the presence of model uncertainty;​ (ii) control of redundant robots in the the presence of obstacles in the environment;​ (iii) optimal control of redundant robots;​ and (iv) motion and force control of robots in the presence of joint flexibility.

The proposed control of motion and force in the presence of uncertainty is developed based on an adaptive scheme. The adaptive control is used to estimate the unknown constant parameters of the robots, the object, and the environment. Based on Lyapunov stability theory, asymptotic convergence of the motion, contact and internal force errors, and of the parameter errors is obtained.

The problem of control in the presence of obstacles is addressed by defining the extended task space. This space is formed by the regular task subspace and the constraint subspace. Using the method developed for coordinated nonredundunt robots, a solution to motion and force control in the presence of obstacles is proposed.

The optimal control problem focuses on minimizing torque loading at the joints of coordinated redundant robots. Both, locally and globally optimal control laws are developed. Using analytical tools, asymptotic stability of the system is proven

The control problem of nonredundunt robots is also extended to the case of joint flexibility. A unified controller is developed to regulate the motion, the contact and internal forces, and the joint elastic force, and to distribute the load between the robots.

Experimental work has also been conducted to examine the proposed motion and force control scheme for coordinated nonredundant robots. The experimental setup consists of two commercial robots, and custom designed software and hardware for coordinated control of both arms. The experiment has confirmed the results of the theoretical analysis