# How to solve derivatives

### Sebastian Castro (view profile)

on 4 May 2015

Hello,

I'm trying to use a DC motor (combined with a gear box) to make my solid (which I imported from Solidworks) rotate, and to monitor its torque and angular speed. Here's a screenshot of my workspace :

Every time I hit run, it answered

"Not enough input derivatives were provided for one or more Simulink-PS Converter blocks associated with the highlighted Solver Configuration block, for the solver chosen. Implicit solvers (ode23t, ode15s, and ode14x) typically require fewer input derivatives than explicit solvers, and local solvers never require any. You can provide more input derivatives by selecting different options (including turning input filtering on or increasing the number of user-provided input derivatives) on the Input Handling tab of Simulink-PS Converter blocks linked below:

. 'matlabprojet3/Revolute - Rotational Interface/Simulink-PS Converter' (1 required, 0 provided)"

So I tried several solutions including changing the solver to one of those advised,

setting the Revolute-Rotational interface to "filter input", or setting the solver to "local solver". All of these changes lead to this other message when I tried to run :

"Initial conditions solve failed to converge. Nonlinear solver to advance time one step failed to converge due to Linear Algebra error. Failed to solve using iteration matrix.

. Equations of one or more components may be dependent or inconsistent. This can cause problems in transient initialization. Here is the set of components involved: 'matlabprojet3/Ideal Torque Sensor' Equation location is: 'C:/Program Files/MATLAB/R2013a/toolbox/physmod/simscape/library/m/+foundation/+mechanical/+sensors/torque.ssc' (line 37)

'matlabprojet3/Revolute - Rotational Interface/Angular Velocity Source' Equation location is: 'C:/Program Files/MATLAB/R2013a/toolbox/physmod/simscape/library/m/+foundation/+mechanical/+sources/angular_velocity.ssc' (line 37)

'matlabprojet3/Revolute - Rotational Interface/Torque Sensor' Equation location is: 'C:/Program Files/MATLAB/R2013a/toolbox/physmod/simscape/library/m/+foundation/+mechanical/+sensors/torque.ssc' (line 37)"

I'm not really used to using Matlab but I searched around it and on the internet and didn't find how to fix this. Could you please tell me how to get this to work and to get some results in the scopes ?

Source: www.mathworks.comCategory: Bank

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