How to figure Torque-frequency diagram for different load inertias?

[junjun55]

I want to learn about the feasible torque bandwidth for electrically driven torque controllable . Can the simulation analysis code of this article “What is the Torque Bandwidth of this Actuator?”be added?

[joernmalzahn]

Hi Junjun,

not sure, if I get your question right. Please have a look at this part of the documentation. It details the torque bandwidth maps. Probably the second graph is what you would like to achieve?

For the code, have a look at dataSheetGenerator.m starting from line 377:

 function h = drawTorqueFrequencyCurveLoad(this, fMax, plotNormalized)
            % DRAWTORQUEFREQUENCYCURVELOAD Theoretically feasible torque bandwidth under varying load inertia.
            %
            % Creates a contour plot that displays the -3dB cut-off frequency for the torque transfer function magnitude 
            % when the actuator generates peak torque. The contour lines are color coded on a logarithmic scale and 
            % correspond to different load inertiae in relation to the combined motor and gear inertia.
            %
            % A very light load will causes the actuator to reach the speed generation limit before a substantial torque
            % level can be established. A heavy load results in torques building up rapidly, with little actuator 
            % motion.
            %
            % The red curve corresponds to an infinite load inertia, that is equivalent to a locked output. The balck
            % solid curve corresponds to the load inertia being equal to the combined motor/gear inertia.
            % 
            % The plot includes the bandwidth limit due to the interplay of spring stiffness and back-EMF generation. 
            % The red area indicates the reachable operating conditions under the assumption of negligible spring 
            % damping. The zone expands with growing sping damping as indicated by black dotted curves. 
            %
            % One axis displays the final temperature at the given
            % operating condition. The second axis displays the time to
            % reach the maximum allowed temperature.
            %
            %   h = drawTorqueFrequencyCurveLoad(this, fMax, plotNormalized)
            %
            % Inputs:
            %   fMax           - The frequency in Hz up to which the magnitude is analyzed (default 100 Hz).
            %   plotNormalized - If true, the frequency axis is normalized to the frequency sqrt( k_ml/(I_m + I_g) ),
            %                    while the torque axis is normalized to the peak torque t_p (default 0). 
            %
            % Outputs:
            %   hContour: Handle to the contour plot
            %   
            %
            % Notes::
            %   For further reading, see: 
            %   J. Malzahn, N. Kashiri, W. Roozing, N. Tsagarakis and D. Caldwell, "What is the torque bandwidth of 
            %   this actuator?," 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 
            %   Vancouver, BC, 2017, pp. 4762-4768. doi: 10.1109/IROS.2017.8206351

[junjun55]

That's it! Many thanks for your clarification! Your research is very worthy learning for me!

[joernmalzahn]

You are welcome.