When imposing the trajectory of a driven joint, all the coordinate, velocity and acceleration must be provided and consistent. Some common trajectories have been defined in the MBsysC source code as well as the tools to combine trajectories.
Find below some of the implemented trajectories. More are available in mbs_trajectories.h.
A cosine trajectory is implemented by the function mbs_cosine_signal() while the sine trajectory is done by mbs_sine_signal() .
The simpliest shape of a ramp (with consistent coordinate, velocity and acceleration) is achieved by imposing a step of constant acceleration, followed by a step at constant velocity and ending with a constant deceleration to reach the wanted ramp height in coordinate, at null velocity.
Such ramp is implemented with the function mbs_ramp_2_order_3_piece_from_acc_vel(). In this function, you impose the acceleration, deceleration and constant velocity. On the other side with the function mbs_ramp_2_order_3_piece() you impose the time of each step (start of acceleration, constant velocity...) and the function will determine the required acceleration, deceleration and velocity.
Other ramps are defined using other intermediate shape between the initial and final coordinates, explore the functions in mbs_trajectories.h.
In some case you may require to combine trajectories, the simplest case being coordinate making a ramp in a direction and then a second ramp to come back to its inital position. Such a trajectory is achieved by adding to ramp of opposite amplitude.
We provide four fonction to combine trajectories:
You can uses the functions with trajectories you defined yourself as it just required the current position, velocity and acceleration of the two trajectories to combine.
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