Kinematics and Compliance

When the DIF is evaluated during statics and quasi-statics, the derivative of the Solver Differential Equation is set to zero. The result is that a Force is generated by the DIF that forces the measured wheel displacement to follow the command wheel displacement.

The forces for each direction are defined using expressions as listed below.

`SHF(time,60,{ds_travel.max_long_force.value},0.1*PI,0,0)*
STEP(TIME,60,0,60.01,1)*STEP(TIME,79.9,1,80,0)`

The expression contains a simple harmonic function that applies a sinusoidal force input, whose value is defined in the KnC Parameter Dataset, at a frequency of 0.1PI between 60 to 80 seconds.

`SHF(time,20,{ ds_travel.max_lat_force.value},0.2*PI,0,0)*
STEP(TIME,20,0,20.01,1)*STEP(TIME,39.9,1,40,0)`

The expression contains a simple harmonic function that applies a sinusoidal force input, whose value is defined in the KnC Parameter Dataset, at a frequency of 0.2PI between 20 to 40 seconds.

`SHF(time,40,{ds_travel.max_algn_torq.value},0.2*PI,0,0)*
STEP(TIME,40,0,40.01,1)*STEP(TIME,59.9,1,60,0)`

The expression contains a simple harmonic function that applies a sinusoidal torque input, whose value is defined in the KnC Parameter Dataset, at a frequency of 0.2PI between 40 to 60 seconds.

`SHF(time,60,{ds_travel.max_long_force.value},0.1*PI,0,0)*
STEP(TIME,60,0,60.01,1)*STEP(TIME,79.9,1,80,0)`

The expression contains a simple harmonic function that applies a sinusoidal force input, whose value is defined in the KnC Parameter Dataset, at a frequency of 0.1PI between 60 to 80 seconds.

`SHF(time,20,{ds_travel.max_lat_force.value},0.2*PI,0,0)*
STEP(TIME,20,0,20.01,1)*STEP(TIME,29.9,1,30,0)-SHF(time,30,{ds_travel.max_lat_force.value},0.2*PI,0,0)*
STEP(TIME,30,0,30.01,1)*STEP(TIME,39.9,1,40,0)`

The expression contains a simple harmonic function that applies a sinusoidal force input, whose value is defined in the KnC Parameter Dataset, at a frequency of 0.2PI between 20 to 40 seconds. For the first 10 seconds between 20 – 30 seconds, the force is positive Y direction and negative Y for the next 10 seconds. This is done to simulate parallel and opposing lateral forces with respect to the left wheel.

`SHF(time,40,{ds_travel.max_algn_torq.value},0.2*PI,0,0)*
STEP(TIME,40,0,40.01,1)*STEP(TIME,49.9,1,50,0)-SHF(time,50,{ds_travel.max_algn_torq.value},0.2*PI,0,0)*
STEP(TIME,50,0,50.01,1)*STEP(TIME,59.9,1,60,0)`

The expression contains a simple harmonic function that applies a sinusoidal torque input, whose value is defined in the KnC Parameter Dataset, at a frequency of 0.2PI between 40 to 60 seconds. For the first 10 seconds between 40 – 50 seconds, the torque is in the same direction as the left wheel and opposite to it for the next 10 seconds. This is done to simulate parallel and opposing aligning torques with respect to the left wheel.

`(AY({mrk_kp.l.idstring},{MODEL.Global_Frame.idstring})) *RTOD`

`-(AX({mrk_kp.l.idstring},{MODEL.Global_Frame.idstring})) *RTOD`

`(AY({mrk_kp.r.idstring},{MODEL.Global_Frame.idstring})) *RTOD`

`(AX({mrk_kp.r.idstring},{MODEL.Global_Frame.idstring})) *RTOD`

{sim_time = sim_data.end_time.value
 print_int = sim_data.print_interval.value
 if(sim_time>20)
 ride_roll_time = 20
 else
 ride_roll_time = sim_time
 endif}

<ResOutput      
       plt_angle   = "YAW_PITCH_ROLL"    
/>    
<ResOutput
       mrf_file    = "TRUE" 
/>  
  <ResOutput
       plt_file    = "TRUE"    
/>   
 <H3DOutput 
       switch_on   = "TRUE"    
       increment   = "1" 
/>  
  <ResOutput 
       abf_file    = "TRUE" 
/>

<Deactivate	
	element_type = "MOTION"
	element_id   = "{mot_spin.l.idstring}"  
/>
<Deactivate	
	element_type = "MOTION"
	element_id   = "{mot_spin.r.idstring}"  
/>
 

<Simulate       
	analysis_type  = "Static" 
      	end_time       = "{ride_roll_time}"      
 	print_interval = "{print_int}"    
/>

{if(sim_time>20)}
<Activate	
	element_type = "MOTION"
	element_id  = "{mot_spin.l.idstring}"  
/>
<Activate	
	element_type = "MOTION"
	element_id  = "{mot_spin.r.idstring}"  
/>
<Simulate       
	analysis_type       = "Static" 
      	end_time            = "{sim_time}"      
 	print_interval      = "{print_int}"    
/>
{endif} 

<Stop/>