SAMPLE_TEAM.Soccer.Motion.compute_Alpha_v3
The module is designed by team Robokit of Phystech Lyceum and team Starkit of MIPT under mentorship of Azer Babaev. Module can be used for Inverted Kinematics for legs of Robokit-1 robot. Advantage of module against other IK implementations is fast and repeatable calculation benchmark. Result is achieved due to mixed analytic/numerical calculation method. Module is designed for 6 DOF robot leg. From 6 angles one angle is calculated using numerical iterations, other 5 angles are obtained through polynom roots formula calculation. This way prowides fast benchmark and repeatability. Algorithm being implemented in C language with integration into firnware of OpenMV is capable to calculated angles for robot legs within time less than 1ms. Multiple IK solutions are filtered through applying of angle limits within calculation. This yields less time for calculation. usage: create class Alpha instance and call method compute_Alpha_v3 with arguments. Returns list of 0, 1 or 2 lists of servo angles. List of 0 elements means that IK was not solved. List of 1 list means 1 possible solition is detected. List of 2 lists means that plurality of solutions was not filtered by provided arguments.
Module Contents
Classes
Attributes
- class SAMPLE_TEAM.Soccer.Motion.compute_Alpha_v3.Alpha[source]
- compute_Alpha_v3(self, xt, yt, zt, x, y, z, w, sizes, limAlpha)[source]
- usage: list: angles = self.compute_Alpha_v3(float: xt, float: yt, float: zt,
float: x, float: y, float: z, float: w, list: sizes, list: limAlpha)
- angles: list of floats angles in radians of servos which provide target positioning and
orientation of robots’ foot
xt: target x coordinate of foots’ center point yt: target y coordinate of foots’ center point zt: target z coordinate of foots’ center point x: x coordinate of vector of orientation of foot y: y coordinate of vector of orientation of foot z: z coordinate of vector of orientation of foot w: rotation in radians of foot around vector of orientation sizes: list of sizes defining distances between servo axles in biped implementation limAlpha: list of limits [minimum, maximum] of servomotors measured in number of encoder ticks
of Kondo series 2500 servomotors.
Target coordinates are measured in local robot coordinate system XYZ with ENU orientation. [0,0,0] point of coordinate system is linked to pelvis of robot. Foot orientation vector has length 1. Base of vector is at bottom of foot and tip of vector is directed down when foot is on floor.