%ACCEL Compute manipulator forward dynamics%%	QDD = ACCEL(ROBOT, Q, QD, TORQUE)%	QDD = ACCEL(ROBOT, [Q QD TORQUE])%% Returns a vector of joint accelerations that result from applying the % actuator TORQUE to the manipulator ROBOT in state Q and QD.%% Uses the method 1 of Walker and Orin to compute the forward dynamics.% This form is useful for simulation of manipulator dynamics, in% conjunction with a numerical integration function.%% See also: RNE, ROBOT, ODE45.% MOD HISTORY% 4/99 add object support% 1/02 copy rne code from inertia.m to here for speed% $Log: not supported by cvs2svn $% $Revision: 1.3 $% Copyright (C) 1999-2008, by Peter I. Corke%% This file is part of The Robotics Toolbox for Matlab (RTB).% % RTB is free software: you can redistribute it and/or modify% it under the terms of the GNU Lesser General Public License as published by% the Free Software Foundation, either version 3 of the License, or% (at your option) any later version.% % RTB is distributed in the hope that it will be useful,% but WITHOUT ANY WARRANTY; without even the implied warranty of% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the% GNU Lesser General Public License for more details.% % You should have received a copy of the GNU Leser General Public License% along with RTB.  If not, see <http://www.gnu.org/licenses/>.function qdd = accel(robot, Q, qd, torque)	n = robot.n;	if nargin == 2,	        q = Q(1:n);		qd = Q(n+1:2*n);		torque = Q(2*n+1:3*n);	else		q = Q;		if length(q) == robot.n,			q = q(:);			qd = qd(:);		end	end	% compute current manipulator inertia	%   torques resulting from unit acceleration of each joint with	%   no gravity.	M = rne(robot, ones(n,1)*q', zeros(n,n), eye(n), [0;0;0]);	% compute gravity and coriolis torque	%    torques resulting from zero acceleration at given velocity &	%    with gravity acting.	tau = rne(robot, q', qd', zeros(1,n));		qdd = inv(M) * (torque(:) - tau');