To build autonomous robots capable to plan and control tasks in human environments, we need a description of trajectories that allows the robot to reason on his moves. In this paper we propose to use series of cubic polynomial curves to define the trajectories with bounded jerk, acceleration and velocity. This solution is well adapted to plan safe and acceptable moves of the robot in the vicinity of humans. It is also a simple solution to approximate any trajectory and synchronize different robots or element of the robots. These curves have a simple representation, can be computed quickly and when used in a fitting algorithm can build controller.

Human interaction introduces two main constraints: safety and comfort. Therefore service robot manipulator canpsilat be controlled like industrial robotic manipulator where personnel is isolated from the robotpsilas work envelope. In this paper, we present a soft motion trajectory planner to try to ensure that these constraints are satisfied. This planner can be used on-line to establish visual and force control loop suitable in presence of human. The cubic trajectories build by this planner are good candidates as output of a manipulation task planner. The obtained system is then homogeneous from task planning to robot control. The soft motion trajectory planner limits jerk, acceleration and velocity in cartesian space using quaternion. Experimental results carried out on a Mitsubishi PA10-6CE arm are presented.