[BUG] The subclasses of DQ_SerialManipulator allow the use of any type of joints

[juanjqo]

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Bug description
@dqrobotics/developers

(Hi @bvadorno, I am working on a proposal to fix the bug I'm reporting here)

At the time being, the classes DQ_SerialManipulatorDH and DQ_SerialManipulatorMDH only support revolute and prismatic joints. However, both class constructors allow any type of joint of the class DQ_JointType.

To Reproduce

For example, this code creates a serial manipulator using types of joints different from revolute and prismatic ones.

Code

clear all;
clc;
close all;

ax18_DH_theta   = [0       0      -pi/2   -pi/2      -pi/2];  % theta
ax18_DH_d       = [0.167   0       0     0.1225          0];  % d
ax18_DH_a       = [0      0.159    0.02225    0      0.170];  % a
ax18_DH_alpha   = [-pi/2   0      -pi/2   -pi/2          0];  % alpha

H  = double(DQ_JointType.HELICAL);
S  = double(DQ_JointType.SPHERICAL);
C  = double(DQ_JointType.CYLINDRICAL);
PL = double(DQ_JointType.PLANAR);
SD = double(DQ_JointType.SIX_DOF);

ax18_DH_type    = [SD PL H S C];

ax18_DH_matrix = [  ax18_DH_theta;
    ax18_DH_d;
    ax18_DH_a;
    ax18_DH_alpha;
    ax18_DH_type;
    ]; 

ax = DQ_SerialManipulatorDH(ax18_DH_matrix)

Output

ax = 

  DQ_SerialManipulatorDH with properties:

               theta: [0 0 -1.5708e+00 -1.5708e+00 -1.5708e+00]
                   d: [1.6700e-01 0 0 1.2250e-01 0]
                   a: [0 1.5900e-01 2.2250e-02 0 1.7000e-01]
               alpha: [-1.5708e+00 0 -1.5708e+00 -1.5708e+00 0]
                type: [6 2 7 3 4]
    JOINT_ROTATIONAL: 1
     JOINT_PRISMATIC: 2
            effector: [1×1 DQ]
             plotopt: {}
             lineopt: {'Color'  'black'  'Linewidth'  [2]}
              handle: []
             n_links: 5
                name: '0.049469'
     reference_frame: [1×1 DQ]
          base_frame: [1×1 DQ]
                   q: []

Expected behavior

• I expect an exception pointing out the use of unsupported types of joints.

Expected output

Something like:

Error using DQ_SerialManipulator/check_type_of_joints
Unsupported types of joints. Valid type of joints: DQ_JointType.REVOLUTE,
DQ_JointType.PRISMATIC.

Environment:

• OS: [e.g. Windows 11]
• dqrobotics version (current version of the master branch)
• MATLAB 2022a

[bvadorno]

Hi @juanjqo,

May you implement it in a new pull request? There is no rush because I’ll be off for one week.

Best wishes,
Bruno

[juanjqo]

Hi @bvadorno, sure!