Figure 1: Dual-arm unilateral cooperative grasping. Figure 3: Projection of the forces f; and f, on the coordinate frame F}. Figure 4: Dual-arm trajectory planning. Fo and Fy) are parameterized in terms of the parameter s: Figure 5: Admittance control scheme adopted for the dual-arm manipulation. Figure 7: The four paths prescribed for the dual-arm tests. Figure 9: Object-velocity profiles for the 6D motions: (a) 6D1-motion; (b) 6D2-motion. Figure 10: Optimization results with a constant internal force f,: (a) 3D1-motion; (b) 3D2-motion; (c) 6D1-motion; (d) 6D2-motion. Figure 12: Ratios between the joint velocities and their maximum values in the opti- mization results with a constant internal force f,: (a) 6D1-motion; (b) 6D2-motion. Table 2: Initial, maximum and mean values of the internal prestress f, obtained as a result of the time-optimal trajectory planning, with an indication of the final time t, of the corresponding trajectory. Figure 13: Experimental dual-arm setup. Figure 14: Assessment of the friction-cone condition with a constant internal force f,: (a) 3D1-motion; (b) 3D2-motion; (c) 6D1-motion; (d) 6D2-motion. Figure 16: Assessment on the application of the net wrench on the object and the gripper for the 3D1-motion: (a) Constant internal force f,; (b) Varying internal force fp. Figure 17: Assessment on the application of the net wrench on the object and the gripper for the 3D2-motion: (a) Constant internal force f,; (b) Varying internal force fy. Figure 18: Assessment on the application of the net wrench on the object and the gripper for the 6D1-motion: (a) Constant internal force f,; (b) Varying internal force fp. Figure 19: Assessment on the application of the net wrench on the object and the gripper for the 6D2-motion: (a) Constant internal force f,; (b) Varying internal force f,.
