stewart-simscape/active-damping.org

Stewart Platform - Active Damping

• Inertial Control
  • Simscape Model
  • Initialize the Stewart model
  • Identification of the Dynamics
  • Analysis
  • Conclusion

Inertial Control

Simscape Model

  open('simulink/stewart_active_damping.slx')

Initialize the Stewart model

  stewart = initializeFramesPositions('H', 90e-3, 'MO_B', 45e-3);
  stewart = generateCubicConfiguration(stewart, 'Hc', 40e-3, 'FOc', 45e-3, 'FHa', 5e-3, 'MHb', 5e-3);
  stewart = computeJointsPose(stewart);
  stewart = initializeStrutDynamics(stewart, 'Ki', 1e6*ones(6,1), 'Ci', 1e2*ones(6,1));
  stewart = initializeCylindricalPlatforms(stewart);
  stewart = initializeCylindricalStruts(stewart);
  stewart = computeJacobian(stewart);
  stewart = initializeStewartPose(stewart);

Identification of the Dynamics

  %% Options for Linearized
  options = linearizeOptions;
  options.SampleTime = 0;

  %% Name of the Simulink File
  mdl = 'stewart_active_damping';

  %% Input/Output definition
  clear io; io_i = 1;
  io(io_i) = linio([mdl, '/F'],   1, 'openinput');  io_i = io_i + 1;
  io(io_i) = linio([mdl, '/WVB'], 1, 'openoutput'); io_i = io_i + 1;
  io(io_i) = linio([mdl, '/Dm'],  1, 'openoutput'); io_i = io_i + 1;

  %% Run the linearization
  G = linearize(mdl, io, options);
  G.InputName  = {'F1', 'F2', 'F3', 'F4', 'F5', 'F6'};
  G.OutputName = {'Vx', 'Vy', 'Vz', 'Wx', 'Wy', 'Wz', ...
                  'D1', 'D2', 'D3', 'D4', 'D5', 'D6'};

Analysis

  freqs = 2*pi*logspace(1, 4, 1000);

  figure;
  bode(G({'D1', 'D2', 'D3', 'D4', 'D5', 'D6'}, {'F1', 'F2', 'F3', 'F4', 'F5', 'F6'}), freqs)

  figure;
  bode(stewart.J*G({'Vx', 'Vy', 'Vz', 'Wx', 'Wy', 'Wz'}, {'F1', 'F2', 'F3', 'F4', 'F5', 'F6'}), freqs)

  figure;
  bode(G({'D1', 'D2', 'D3', 'D4', 'D5', 'D6'}, {'F1', 'F2', 'F3', 'F4', 'F5', 'F6'}), stewart.J*G({'Vx', 'Vy', 'Vz', 'Wx', 'Wy', 'Wz'}, {'F1', 'F2', 'F3', 'F4', 'F5', 'F6'}), freqs)

Conclusion

It is similar to use:

• one 6dof inertial sensor and the Jacobian the have the velocity of each lim
• 6 1dof inertial sensor in each top part of the limbs