New Servosila SC-60 brushless motor controllers are now available for purchase.

The new controllers bring up to 45A (30Arms) nominal motor current while sharing the same form factor as the venerable SC-25 controllers, thus providing an in-place upgrade capability
(datasheet).

The controllers come in two form factors, a rectangular (SC-60R) and a circular (SC-60C) one. This time, the circular version has a smaller diameter and comes with a central inner diameter specifically designed for passing rotating shafts or cables through the board.

The SC-60 controllers support a wide range of encoder interfaces (BISS/SSI, SPI, Quadrature, PWM) thus making them ideal for actuating powerful high-precision servomechanisms such as robotic arms or sensor pan-tilt-roll mechanisms or traction motors.

The controllers provide an open CAN/CANopen and an open USB control interfaces and come prepackaged with open-source sample software code that utilizes the interfaces directly without using any closed source libraries.

Listen to the sound of 32 000 RPM

This little 4-pole electric turbine makes roughly 535 revolutions per second under the control of a Servosila SC-60R controller.

Medical applications often require high-speed motors. There is a section in the datasheet that gives rules of thumb that help select a higher-speed motor for use with the SC-60 controllers.

Although SC-60 controllers are primarily intended for servo applications where the motors have to move rather slowly, but with the highest precision possible, the SC-60 demonstrates an improved performance when driving higher-speed low-inductance motors such as the one shown in this demo.

Low inductance motors are notoriously hard to drive reliably. It turned out that features introduced in SC-60's design due to requirements of precision servo control improved performance at the higher speeds as well.

Servosila recently completed a challenging project called "Tracking Telescope" that we would like to tell about.

A customer, an established telescope manufacturer, required a very high precision of motion control at very low speeds for a two-axis direct-drive telescope fixture. The fixtures are equipped with Servosila SC-25C servo drives and Renishaw 26bit optical encoders.

The telescopes are about 2meters long and are pretty heavy due to powerful optics. The positioning tolerance requirement is ~1.0 arc-second which calls for about 21bits of effective positioning accuracy with the 26bit encoders.

Furthermore, since celestial objects keep moving, this accuracy has to be maintained while tracking objects moving at speeds of up to 2.0 degrees per second. This corresponds to RPMs in the range of Zero to 0.30 RPM. Moving at such low speeds is a challenge in its own right.

An extensive use of Servoscope simulation software helped identify an envelop of configuration parameters that allowed the SC-25C servo drives to meet or exceed the tolerance requirements as well as the tracking performance requirements. It took a clever application of Velocity Feed Forward Signal in a PID loop to make such tracking possible.

We are soon publishing a technical paper that records the experiences and details a tuning procedure for Servosila SC-25C servo drives that resulted in the required performance.

Here is a quick update on the tracking telescope project. The telescope is equipped with a dual-axis direct-drive mount with 26-bit optical encoders.

A Servosila team working on the project managed to improve the control laws so that more noise is rejected, and got to the following improved results:
- The static angular positioning accuracy is now 25bits out of 26bits.
- The dynamic tracking accuracy at angular speeds of ~2deg/sec is 22-23bits.

These are nearly perfect results as far as what can be possibly achieved with 26bit encoders in real life settings.

The good news is that the improvements in the firmware and the control laws are now shipped with all stock SC-series controllers (SC-25 & SC-60), so that you could achieve similar results in your applications, too !

This is a video of a Tether Management System that was sent to us by one of the users of Servosila SC25 servo drives. The system is designed to deploy underwater equipment such as ROVs or sonars from unmanned vehicles. The system uses two SC-25C controllers and a clever user-built software that commands them.
#HybridRobotics

The new Servosila SC-60C brushless servocontrollers are now in stock!

The SC-60C motor controllers feature a form factor optimized for servos with hollow shafts. The outer diameter is 60mm, the inner diameter is 24mm.

Up to 35A of continuous current and up to 32bit of encoder resolution are supported. The input voltage is 7V to 60V DC.

The controllers are suitable for high-resolution applications such as optical instruments, for certain traction applications such as mid-sized electrical drones as well as for robotic quadrupeds, cobots and precision CNC machines.

Servoscope software comes with a built-in 3D humanoid model and an instance of Servosila Motion Controller attached to it. The model has 34 degrees of freedom and is actuated by simulated Servosila SC-60 servo drives.

The Motion Controller is scripted via CANopen, G-code or DLL API in any programming language such as Python or C++. The CANopen interface is exactly the same as that of physical servo drives.

As shown in the demo, it takes a few lines of script in G-code to get the humanoid's arm to draw a circle in space.

The Motion Controller software uses an inverse kinematics (IK) technique to automatically produce control laws for each individual joint of the robot, so that the tool of the arm follows a 3D spline trajectory. The technique also enforces various motion constraints along the path.

Servosila Motion Controller is distributed free of charge with all Servosila's servo drives (SC-60, SC-25) and is designed to provide an out-of-the-box control solution for #CNC machines as well as #robots.

Servosila SC-series servo drives, when paired with Inertial Measurement Units (IMUs), are often used for high-bandwidth gyro-stabilization applications. It is possible to stabilize jumbo payloads within very tight tolerances.

Servosila Motion Controller, a free-to-use software package, provides a straightforward way to define stabilization laws that fuse data streams coming from Servosila SC-series servo drives and off-the-shelf third-party IMU/GNSS sensors.

Behavior trees of mobile #robots, especially walking ones, heavily rely on IMUs for whole-body motion control, gait generation, stabilization, obstacle detection, numerical optimization techniques and so on.

Servosila Motion Controller supports up to 20 IMUs per single robotic kinematic model. By the way, it takes 17 IMUs to capture motion of a human body.

A 3D simulator built into Servosila Motion Controller, allows creating Hardware-in-the-Loop (HIL) simulations of #CNC, #UGV, #USV or #UAV systems that make use of the data coming from IMUs.

Electronic Gearing or Master-Follower is a built-in function of Servosila SC-series servo drives. The function tightly controls motion of two or more axes making it look like the axes are interconnected by an invisible belt. The motion of a "follower" axis is electronically synchronized with a "master" axis in both velocity and position. The gearing ratios (e g. 1:1 or 1:10) are software-controlled, including possibility of on-the-fly real-time ratio changes.

The master axis needs to be equipped with a pulse output sensor such as a Hall sensor or an optical tachometer sensor. An SC-series controller then takes in the pulse as an input and controls the "follower" motor in such a way that the traveled distance and velocity match those of the master axis. This creates a virtual gearing connection between the axes.

The feature is used in textile machines, Wire #EDM machines, CNC #skiving machines, conveyors, gantry machines and in agricultural equipment.