vel_xy_forward = vel_xy_current + bound(0, wishspeed - vel_xy_current, step) * accelqw + step * (1 - accelqw);
vel_xy_backward = vel_xy_current - bound(0, wishspeed + vel_xy_current, step) * accelqw - step * (1 - accelqw);
if(vel_xy_backward < 0)
vel_xy_forward = vel_xy_current + bound(0, wishspeed - vel_xy_current, step) * accelqw + step * (1 - accelqw);
vel_xy_backward = vel_xy_current - bound(0, wishspeed + vel_xy_current, step) * accelqw - step * (1 - accelqw);
if(vel_xy_backward < 0)