%RobotArm Serial-link robot arm class

%

% A subclass of SerialLink than includes an interface to a physical robot.

%

% Methods::

%

% plot display graphical representation of robot

%-

% teach drive the physical and graphical robots

% mirror use the robot as a slave to drive graphics

%-

% jmove joint space motion of the physical robot

% cmove Cartesian space motion of the physical robot

%

% plus all other methods of SerialLink

%

% Properties::

%

% as per SerialLink class

%

% Note::

% - the interface to a physical robot, the machine, should be an abstract

% superclass but right now it isn't

% - RobotArm is a subclass of SerialLink.

% - RobotArm is a reference (handle subclass) object.

% - RobotArm objects can be used in vectors and arrays

%

% Reference::

% - http://www.petercorke.com/doc/robotarm.pdf

% - Robotics, Vision & Control, Chaps 7-9,

% P. Corke, Springer 2011.

% - Robot, Modeling & Control,

% M.Spong, S. Hutchinson & M. Vidyasagar, Wiley 2006.

%

% See also Machine, SerialLink, Link, DHFactor.

% Copyright (C) 1993-2017, 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/>.

%

% http://www.petercorke.com

classdef RobotArm < SerialLink

properties

machine

ngripper

end

methods

function ra = RobotArm(robot, machine, varargin)

%RobotArm.RobotArm Construct a RobotArm object

%

% RA = RobotArm(L, M, OPTIONS) is a robot object defined by a vector of

% Link objects L with a physical robot interface M represented by an object

% of class Machine.

%

% Options::

%

% 'name', name set robot name property

% 'comment', comment set robot comment property

% 'manufacturer', manuf set robot manufacturer property

% 'base', base set base transformation matrix property

% 'tool', tool set tool transformation matrix property

% 'gravity', g set gravity vector property

% 'plotopt', po set plotting options property

%

% See also SerialLink.SerialLink, Arbotix.Arbotix.

ra = ra@SerialLink(robot, varargin{:});

ra.machine = machine;

ra.ngripper = machine.nservos - ra.n;

end

function delete(ra)

%RobotArm.delete Destroy the RobotArm object

%

% RA.delete() closes and destroys the machine interface object and the RobotArm

% object.

% attempt to destroy the machine interfaace

try

ra.machine.disconnect();

delete(ra.machine);

catch

end

% cleanup the parent object

delete@SerialLink(ra);

end

function jmove(ra, qf, t)

%RobotArm.jmove Joint space move

%

% RA.jmove(QD) moves the robot arm to the configuration specified by

% the joint angle vector QD (1xN).

%

% RA.jmove(QD, T) as above but the total move takes T seconds.

%

% Notes::

% - A joint-space trajectory is computed from the current configuration to QD.

%

% See also RobotArm.cmove, Arbotix.setpath.

if nargin < 3

t = 3;

end

q0 = ra.getq();

qt = jtraj(q0, qf, 20);

ra.machine.setpath(qt, t/20);

end

function cmove(ra, T, varargin)

%RobotArm.cmove Cartesian space move

%

% RA.cmove(T) moves the robot arm to the pose specified by

% the homogeneous transformation (4x4).

%

% Notes::

% - A joint-space trajectory is computed from the current configuration to

% QD using the jmove() method.

% - If the robot is 6-axis with a spherical wrist inverse kinematics are

% computed using ikine6s() otherwise numerically using ikine().

%

% See also RobotArm.jmove, Arbotix.setpath.

if ra.isspherical()

q = ra.ikine6s(T, varargin{:});

else

q = ra.ikine(T, ra.getq(), [1 1 1 1 0 0]);

end

ra.jmove(q);

end

function q = getq(ra)

%RobotArm.getq Get the robot joint angles

%

% Q = RA.getq() is a vector (1xN) of robot joint angles.

%

% Notes::

% - If the robot has a gripper, its value is not included in this vector.

q = ra.machine.getpos();

q = q(1:ra.n);

end

function mirror(ra)

%RobotArm.mirror Mirror the robot pose to graphics

%

% RA.mirror() places the robot arm in relaxed mode, and as it is moved by

% hand the graphical animation follows.

%

% See also SerialLink.teach, SerialLink.plot.

h = msgbox('The robot arm will go to relaxed mode, type q in the figure window to exit', ...

'Mirror mode', 'warn');

ra.machine.relax();

while true

if get(gcf,'CurrentCharacter') == 'q'

break

end;

q = ra.machine.getpos();

ra.plot(q(1:ra.n));

end

ra.machine.relax([], false);

delete(h);

end

function teach(ra)

%RobotArm.teach Teach the robot

%

% RA.teach() invokes a simple GUI to allow joint space motion, as well

% as showing an animation of the robot on screen.

%

% See also SerialLink.teach, SerialLink.plot.

q0 = ra.machine.getpos();

teach@SerialLink(ra, 'q0', q0(1:ra.n), ...

'callback', @(q) ra.machine.setpos([q q0(ra.n+1)]) );

end

function gripper(ra, open)

%RobotArm.gripper Control the robot gripper

%

% RA.gripper(C) sets the robot gripper according to C which is 0 for closed

% and 1 for open.

%

% Notes::

% - Not all robots have a gripper.

% - The gripper is assumed to be the last servo motor in the chain.

if open < 0 || open > 1

error('RTB:RobotArm:badarg', 'gripper control must be in range 0 to 1');

end

if ra.ngripper == 0

error('RTB:RobotArm:nofunc', 'robot has no gripper');

end

griplimits = ra.machine.gripper;

a = open*griplimits(1) + (1-open)*griplimits(2)

ra.machine.setpos(ra.n+1, a);

end

end

end