In this paper, we consider folding assembly as an assembly primitive suitable for dual-arm robotic assembly, that can be integrated in a higher level assembly strategy. The system composed by two pieces in contact is modelled as an articulated object, connected by a prismatic-revolute joint. Different grasping scenarios were considered in order to model the system, and a simple controller based on feedback linearisation is proposed, using force torque measurements to compute the contact point kinematics. The folding assembly controller has been experimentally tested with two sample parts, in order to showcase folding assembly as a viable assembly primitive.
Robotic assembly with dual-arm manipulators has advantages and poses specific challenges; an in-depth review of the state-of-the-art for dual arm manipulation can be found in @cite_23 . The increased flexibility and larger independence from a structured environment comes at the cost of an increase in system complexity. In particular, interaction forces between the manipulators and grasped objects require careful consideration, due to the closed kinematic chain @cite_14 . While both single and dual arm robots can be used for applying planning strategies @cite_0 @cite_11 @cite_15 , a dual arm robot can take advantage from the cooperation between manipulators that allows for a reduction in task complexity @cite_24 . Several works detail master-slave implementations. When carrying a load, it is common to have one arm perform the motion control of the overall system, while its slave uses force feedback to ensure tracking of the object changing position @cite_10 @cite_9 . Master-slave relationships are also relevant in scenarios where the need to overcome a physical distance between an operator and its work subject is present @cite_19 @cite_8 .
@cite_14 @cite_8 @cite_9 @cite_0 @cite_24 @cite_19 @cite_23 @cite_15 @cite_10 @cite_11
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An approach to the control of constrained dynamic systems such as multiple arm systems, multifingered grippers, and walking vehicles is described. The basic philosophy is to utilize a minimal set of inputs to control the trajectory and the surplus input to control the constraint or interaction forces and moments in the closed chain. A dynamic control model for the closed chain is derived that is suitable for designing a controller in which the trajectory and the interaction forces and moments are explicitly controlled. Nonlinear feedback techniques derived from differential geometry are then applied to linearize and decouple the nonlinear model. These ideas are illustrated through a planar example in which two arms are used for cooperative manipulation. Results from a simulation are used to illustrate the efficacy of the method. > In this paper a real-time collision avoidance approach is presented for safe human-robot coexistence. The main contribution is a fast method to evaluate distances between the robot and possibly moving obstacles (including humans), based on the concept of depth space. The distances are used to generate repulsive vectors that are used to control the robot while executing a generic motion task. The repulsive vectors can also take advantage of an estimation of the obstacle velocity. In order to preserve the execution of a Cartesian task with a redundant manipulator, a simple collision avoidance algorithm has been implemented where different reaction behaviors are set up for the end-effector and for other control points along the robot structure. The complete collision avoidance framework, from perception of the environment to joint-level robot control, is presented for a 7-dof KUKA Light-Weight-Robot IV using the Microsoft Kinect sensor. Experimental results are reported for dynamic environments with obstacles and a human. In this paper the problem of achieving a cooperative behavior in a dual-arm robot systemisaddressed.Acontrolstrategyisconceivedinwhichonerobotispositioncontrolledanddevoted to task execution, whereas a suitable compliance is conferred to the end effectoroftheotherrobottocopewithunavoidablemisalignmentbetweenthetwoarmsandtaskplanning inaccuracies. A modular control structure is adopted that allows the selectionof the proper operating mode for each robot, depending on the task requirements. Theproposed approach is experimentally tested in two different tasks involving the tworobots in the laboratory setup. First, a parts-mating task of peg-in-hole type is executed;the robot carrying the peg is position controlled, whereas the robot holding the hollowpart is controlled to behave as a mechanical impedance. Then, a pressure-forming taskis executed, in which a disk-shaped tool is required to align with a ﬂat surface whileexerting a desired pressure; in this case, the robot carrying the disk is position controlled,whereas the robot holding the surface is force controlled. Minimally invasive surgery involves inserting special instruments into the body cavity through tiny incisions in order to perform surgical procedures. In this paper, the design of a robotic master-slave system for use in minimally invasive surgery is discussed. This system is capable of providing haptic feedback to the surgeon in all available degrees of freedom. System design as well as master and slave bilateral control and communication issues are discussed. This paper proposes a control scheme which realizes cooperative motion to handle a target object by using two robot manipulators. The first robot, which is used as the leader, has only the robust position controller. The second robot, which is used as the follower, has the position based force controller. Based on this very simple strategy, we can easily realize intelligent cooperative manipulation by completely decentralized control. We demonstrate its control performance by experiments of moving an object back and forth, and discuss on future problems.