Engineering Q&A: Surgical Robots with Matthew Dean

We spoke with Matthew Dean, Head of the Medical Business Unit at maxon UK & Ireland, about the growing role of surgical robotics. With over a decade of experience in precision drive systems, he shares insights into current trends, design challenges, and how maxon supports developers in advancing surgical robot technology.

Your Name, Job Title and Responsibilities?

I’m Matthew Dean, head of the medical business unit, for maxon UK & Ireland. My role is to support medical technology design engineers with the specification and design of drive systems. 

Could you tell me a little about your background in the sector?

I’ve worked at maxon for over 10 years, and during that time I’ve focussed on supporting medical technology OEMs by specifying drive systems that optimise the precision of their applications. Following a degree in mechanical engineering from the University of Portsmouth, I worked at Rotalink Ltd, involved in both the Sales and Engineering aspects of miniature power transmission systems for anything from a water softner to an ATM. 

Could you provide a brief summary of your organisation and offering to the market?

With its headquarters in Switzerland, maxon designs and manufactures drive systems involving brushless DC (BLDC) and DC motors, gear heads, encoders, and controls. We focus on supporting applications that require precision and compact design, often involving design customisation to meet specific application needs. Medical applications commonly have these requirements, and as a result, this sector is very important to maxon. 

Who in the main are the companies you engage with and in what way?

In the medical sector, which is a key industry for maxon in the UK & Ireland, we provide drive systems for pumps and medication delivery systems, rehabilitation equipment and prosthetics, as well as active implants, and surgical systems. This includes hand-held surgical tools as well as surgical robot systems, which is a primary focus for us. 
maxon’s UK & Ireland engineering team engage directly with medical technology design engineers to specify the drive system and its component products to meet the specific needs of the application, which can also involve design customisation. 

What do you see as the broad trends taking place across technology for surgery?

We continue to see significant growth in demand for surgical robot systems. In the UK, the NHS has recently announced its aspirations over the next 10 years to provide half a million procedures with robots each year by 2035. The NHS says 9-in-10 of all keyhole surgical procedures will be completed with robotic assistance, compared to around 1-in-5 today. 
We’re also seeing robotics applied to many more types of surgery. As well as conditions such as urological cancer treatment, robotics are applied to colorectal, gynaecology, ear, nose and throat, and orthopaedic procedures. 
This demand is down to the greater dexterity, precision, and repeatability that robotics bring, helping to achieve better patient outcomes with more effective surgery and improved recovery. Increased involvement of surgical robots also has the potential to achieve faster throughput, helping to reduce patient waiting times. 

How is this need impacting the surgical robot market?

Surgical robot developers are looking to raise production while continually looking to design and build robots that are increasingly precise and accurate. This means that they want to develop more quickly, with more efficient processes, while optimising the level of control that their robots can achieve.
The joints in the arms of the robots, comprising the motor, gear, position sensors, brakes, and controls, are vital to achieve movement and precision. What we’re continuing to see is the move away from robot manufacturers developing their own joints, and instead, they’re looking to dedicated motion engineers to provide complete robot joints, ready for integration into the host robot. 
This cuts down their development time, ensures that the right testing and conformance is already reached, and ultimately achieves a better design of joint thanks to the experience and expertise in drive system development. 

What requirements do robot manufacturers have on the development of joints?

Within the confines of a theatre setting, there’s pressure for surgical robots to maintain a compact footprint. While robotic arm joints follow a typical design, involving a hollow central bore that allows the through-routing of cables, they need to ensure a compact length. Robot arms also need to minimise weight to maximise control, so it’s important that robot joints achieve high torque for a given weight. 
Combined with a compact, torque-dense package, precision control is essential for surgical procedures, where micron-level movement, little more than a hair’s width, is required. 

How are developers of robot joints responding to these needs?

To optimise torque density, compact, brushless DC (BLDC) motors are required, and various aspects of its design, such as ironless windings and an optimised winding configuration, can further increase torque while reducing mass. A lightweight, compact gear head that achieves high gear reduction in a single stage can also be used.
To achieve high precision, a zero-backlash gearbox that prevents free movement between gear teeth is also important, and this can be achieved by integrating a strain wave design. Encoder technology, which provides feedback on rotational position, is also required. A surgical robot joint should have an encoder positioned on the rotor to optimise motor control, as well as an additional encoder on the output shaft, with 19-bit resolution that can identify the most precise movement. Control integration is also key, including the capability to command the required kinematic moves across each of the joints at high speed.

What advice would you give to surgical robot developers for joint design and integration?

The joints are crucial for the control and precision that can be achieved by a surgical robot. Multiple design considerations might be required that can impact wider design considerations of the robot. As a result, it’s useful to engage early with a robot joint developer to simplify the design process of the robot overall, and achieve the highest level of performance.

Contact Matthew to discuss your medical application: matthew.dean@maxongroup.com