I’m excited to announce a big price drop for the moteus-r4.11 controller for both single units and in volume!

Quantity	Old	New
1-10	$104	$79
10-99	$99	$75
100-499	$94	$71

We’ve been scaling up production, which enables these reductions of about 25% across the board. moteus-r4 is now by far the most cost effective motor driver with integrated encoder in its class. Here’s a quick comparison with similar products:

	ODRIVE S1	Tinymover R5.2	moteus-r4.11
Voltage	12-50.5V	12-38V	10-44V
Continuous phase current	40A	Not specified	22A
Peak current	80A	40A	100A
Dimensions	66mm x 50mm	40mm x 36mm	53mm x 46mm
Open source	Proprietary FW and HW	GPL FW, Proprietary HW	Apache 2.0 FW and HW
Price	$149	$108	$79

I personally am looking forward to all the new projects that these lower prices enable! Check it out below or join the mjbots Discord to chat and get some ideas for how you can use a moteus-r4.

The moteus brushless motor controller supports several concepts of operation from within its primary “position” mode, including a velocity mode. As documented in the reference, you can run in that scenario using commands equivalent to the diagnostic mode command:

d pos nan V nan

Where V is the desired velocity. However, as with most control operations, there are a number of edge cases that can be useful to handle. When operating purely in velocity mode, the normal PID constants can be interpreted slightly differently:

moteus has long had both automatically tuned current control bandwidth and a built-in low-pass filter for encoder readings. During calibration, these are usually set with moteus_tool’s --cal-bw-hz option, which specifies the current loop (interchangeably called the torque loop) bandwidth. TLDR is that these heuristics have changed as of pypi 0.3.64, hopefully with only improved behavior. Read on if you want to understand more or if you need to resolve problems with something that changed for the worse.