Regbot motor parameters - Revision history

Jca: /* Measured values (Km, R, L) */

2026-01-08T11:30:14Z

Measured values (Km, R, L)

← Older revision		Revision as of 13:30, 8 January 2026
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	ID Name K-left K-right R-left R-right L-left L-right		ID Name K-left K-right R-left R-right L-left L-right
	(V/(rad/sec)) (Ohm) (Ohm) (Henry) (Henry)		(V/(rad/sec)) (Ohm) (Ohm) (Henry) (Henry)
	1 Emma 0.0094 0.0096 2.4 7.8 5.6E-03 6.4E-03		1 Emma 0.0094 0.0096 2.4 7.8 5.6E-03 6.4E-03

Jca: /* Measured values (Km, R, L) */

2026-01-08T11:30:06Z

Measured values (Km, R, L)

← Older revision		Revision as of 13:30, 8 January 2026
Line 24:		Line 24:


	ID Name K-left K-right R-left R-right L-left L-right		ID Name K-left K-right R-left R-right L-left L-right
	(V/(rad/sec)) (Ohm) (Ohm) (Henry) (Henry)		(V/(rad/sec)) (Ohm) (Ohm) (Henry) (Henry)
	1 Emma 0.0094 0.0096 2.4 7.8 5.6E-03 6.4E-03		1 Emma 0.0094 0.0096 2.4 7.8 5.6E-03 6.4E-03

Jca: /* Measured values (Km, R, L) */

2026-01-08T11:29:53Z

Measured values (Km, R, L)

← Older revision		Revision as of 13:29, 8 January 2026
Line 24:		Line 24:


	ID Name Km-left Km-right R-left R-right L-left L-right		ID Name K-left K-right R-left R-right L-left L-right
	(V/(rad/sec)) (Ohm) (Ohm) (Henry) (Henry)		(V/(rad/sec)) (Ohm) (Ohm) (Henry) (Henry)
	1 Emma 0.0094 0.0096 2.4 7.8 5.6E-03 6.4E-03		1 Emma 0.0094 0.0096 2.4 7.8 5.6E-03 6.4E-03

Jca: /* Measured values (Friction and inertia) */

2026-01-08T11:28:42Z

Measured values (Friction and inertia)

← Older revision		Revision as of 13:28, 8 January 2026
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	87 Ronja 0.0111 0.0114 2.5 6.0 2.7E-03 3.2E-03		87 Ronja 0.0111 0.0114 2.5 6.0 2.7E-03 3.2E-03

	== Measured values (Friction and ~~inertia~~)==		== Measured values (Friction and Inertia)==

	These measurements were taken during maintenance in January 2026; not all values were recorded, but the list can serve as a guide when creating a simulated model of the robot.		These measurements were taken during maintenance in January 2026; not all values were recorded, but the list can serve as a guide when creating a simulated model of the robot.

	Dynamic or viscous friction (D) is calculated in a steady state by comparing the velocities and the current difference between the two velocities. Dynamic friction can vary among motors; it depends, e.g., on the ~~actual~~ lubrication, temperature, and ~~the state of the~~ commutator. The estimate is further hampered by the poor current measurement.		Dynamic or viscous friction (D) is calculated in a steady state by comparing the velocities and the current difference between the two velocities. Dynamic friction can vary among motors; it depends, e.g., on the lubrication, temperature, and commutator condition. The estimate is further hampered by the poor current measurement.

	The moment of inertia (J) is estimated from the time required to reach steady-state velocity.		The moment of inertia (J) is estimated from the time required to reach steady-state velocity.
	The actual moment of inertia (J) will be equal across all motors with high accuracy. The variation in estimate indicates a high measurement ~~uncirtancy~~.		The actual moment of inertia (J) will be equal across all motors with high accuracy. The variation in the estimate indicates a high measurement uncertainty.

Jca: /* Motor parameters */

2026-01-08T11:22:16Z

Motor parameters

← Older revision		Revision as of 13:22, 8 January 2026
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	This relies on a poorly designed motor current measurement and noisy velocity measurements.		This relies on a poorly designed motor current measurement and noisy velocity measurements.

	These measurements can be repeated using the Regbot GUI.		These measurements can be repeated using the Regbot GUI. See [[User_interface#Motor_test]].
	There is a tab called Wotor. Run the test a few times to get a sense of the variability in values.		There is a tab called Wotor. Run the test a few times to get a sense of the variability in values.
	It can also be advantageous to warm up the motor lubrication by running a short mission before the test.		It can also be advantageous to warm up the motor lubrication by running a short mission before the test.

Jca: /* Motor parameters */

2026-01-08T11:20:49Z

Motor parameters

← Older revision		Revision as of 13:20, 8 January 2026
Line 6:		Line 6:
	This relies on a poorly designed motor current measurement and noisy velocity measurements.		This relies on a poorly designed motor current measurement and noisy velocity measurements.

			These measurements can be repeated using the Regbot GUI.
			There is a tab called Wotor. Run the test a few times to get a sense of the variability in values.
			It can also be advantageous to warm up the motor lubrication by running a short mission before the test.

	== Measured values (Km, R, L)==		== Measured values (Km, R, L)==

Jca: /* Measured values (Km, R, L) */

2026-01-08T11:17:24Z

Measured values (Km, R, L)

← Older revision		Revision as of 13:17, 8 January 2026
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	== Measured values (Km, R, L)==		== Measured values (Km, R, L)==

	These measurements were taken during maintenance in January 2026; not all values were ~~saved~~, but the list can ~~be used~~ as a guide, when creating a simulated model of the robot.		These measurements were taken during maintenance in January 2026; not all values were recorded, but the list can serve as a guide when creating a simulated model of the robot.

	ID Name K-left K-right R-left R-right L-left L-right		The motor constant (Km) is estimated from the steady-state velocity, the input voltage, and the motor current and resistance. The uncertainty primarily arises from poor current measurement, but also from variation in the permanent magnet strength.

			The motor resistance (R) is estimated from the peak current as the voltage is varied, and before the motor has changed velocity.

			The inductance (L) is estimated from the time it takes to increase the current to steady-state and before the motor has changed velocity. The peak current is used as the steady-state. The current at two times is used to estimate the exponential rise in current, i.e., the time constant of the L/R circuit.
			The sample time used for these measurements is 0.3ms.
			This value may vary across motor generations but should be reasonably constant within them.
			The newer generation of motors typically has a motor constant (Km) of 0.012, where the older versions have a value closer to 0.01. Some motors appear to have a lower value; it could be due to a weaker permanent magnet.


			ID Name Km-left Km-right R-left R-right L-left L-right
	(V/(rad/sec)) (Ohm) (Ohm) (Henry) (Henry)		(V/(rad/sec)) (Ohm) (Ohm) (Henry) (Henry)
	1 Emma 0.0094 0.0096 2.4 7.8 5.6E-03 6.4E-03		1 Emma 0.0094 0.0096 2.4 7.8 5.6E-03 6.4E-03

Jca: /* Measured values (Friction and inertia) */

2026-01-08T11:03:05Z

Measured values (Friction and inertia)

← Older revision		Revision as of 13:03, 8 January 2026
Line 64:		Line 64:
	== Measured values (Friction and inertia)==		== Measured values (Friction and inertia)==

	These measurements were taken during maintenance in January 2026; not all values were ~~saved~~, but the list can ~~be used~~ as a guide, when creating a simulated model of the robot.		These measurements were taken during maintenance in January 2026; not all values were recorded, but the list can serve as a guide when creating a simulated model of the robot.

			Dynamic or viscous friction (D) is calculated in a steady state by comparing the velocities and the current difference between the two velocities. Dynamic friction can vary among motors; it depends, e.g., on the actual lubrication, temperature, and the state of the commutator. The estimate is further hampered by the poor current measurement.

			The moment of inertia (J) is estimated from the time required to reach steady-state velocity.
			The actual moment of inertia (J) will be equal across all motors with high accuracy. The variation in estimate indicates a high measurement uncirtancy.


	ID Name D-left D-right J-left J-right		ID Name D-left D-right J-left J-right

Jca: /* Measured values (Friction and inertia) */

2026-01-08T10:52:51Z

Measured values (Friction and inertia)

← Older revision		Revision as of 12:52, 8 January 2026
Line 66:		Line 66:
	These measurements were taken during maintenance in January 2026; not all values were saved, but the list can be used as a guide, when creating a simulated model of the robot.		These measurements were taken during maintenance in January 2026; not all values were saved, but the list can be used as a guide, when creating a simulated model of the robot.

	ID Name D-left D-right J-left J-right		ID Name D-left D-right J-left J-right
	% (Nm/(rad/sec)) (Nm/(rad/sec)) (Kgm^2) (Kgm^2)		% (Nm/(rad/sec)) (Nm/(rad/sec)) (Kgm^2) (Kgm^2)
	1 Emma 1.2E-06 815.7E-09 1.3E-03 861.8E-06		1 Emma 1.2E-06 815.7E-09 1.3E-03 861.8E-06

Jca: /* Measured values (Friction and inertia) */

2026-01-08T10:52:25Z

Measured values (Friction and inertia)

← Older revision		Revision as of 12:52, 8 January 2026
Line 67:		Line 67:

	ID Name D-left D-right J-left J-right		ID Name D-left D-right J-left J-right
	% (Nm/(rad/sec)) (Kgm^2) (Kgm^2)		% (Nm/(rad/sec)) (Nm/(rad/sec)) (Kgm^2) (Kgm^2)
	1 Emma 1.2E-06 815.7E-09 1.3E-03 861.8E-06		1 Emma 1.2E-06 815.7E-09 1.3E-03 861.8E-06
	2 Sofia 1.4E-06 1.4E-06 1.3E-03 863.2E-06		2 Sofia 1.4E-06 1.4E-06 1.3E-03 863.2E-06