Harvard’s milliDelta Robot Might Be Tiny But Packs Speed and Precision

Harvard’s milliDelta robotics equipmentmight not look much, but this mini-robot’smobility is at millimetre-scale, offering industrial or medical procedure precision at speed beyond capacities previously seen before.  This article takes a look at what this recent robotic innovationmeans.

What are Delta Robots

To understand the uses and implications of delta robots, let’s start with what they are.  According to BARA, the Delta robot consists of a number of “kinematic chains”, or movable, inter-connected parts, with a connected base and links to an ‘end-effector’, (i.e. the component that interacts with its environment, like a substitute human hand).  Mini- and micro-robots are often used to handle small products.

The Harvard milliDelta robot was inspired by origami-engineering.  The mini-robot recently reported on by IEEE, can reach velocities of 0.45 m/s, with accelerations of 215 m/s², Making, detailed movement impossible to see.

In terms of sheer speed and precision, delta robots are incredibly impressive to watchand when we consider potential uses for some industrial or medical processes, their future is mind-blowing.   Currently, delta robots are most commonly used for  pick-and-place tasks in factories as they are often faster than humans and less prone to error, albeit quality control may dictate some minimal human supervision.  

Harvard Microrobotics Labresearcher, Hayley McClintock has designed one of the tiniest delta robots ever, called milliDelta.  It may be small, but it’s one of the fastest moving and most precise robots we’ve ever seen at Infinity Robotics.

Delta robots have two noteworthy features. The first is that despite the highly dynamic and powerful animatronics, its motors are steadfastly stationary. Robotic arms tend to be made up of a series of rigid links and joints that house motors.  This can make a robotic arm very heavy, which would be incompatible with speed.  

However, McClintock moved this robot’s motors to the base. This means there is less mass moving around, allowing milliDelta to accelerate rapidly and move with extreme precision.

The second beneficial element to Delta robots is their ‘end-effectors’, i.e. where the arms meet that they stay parallel to the work surface – delta robots are a type of parallel robot. This makes these robots ideal for pick-and-place manufacturing operations, as they maintain the exact orientation between items needing picking up and placement.

The milliDeltas Vital Statistics

Harvard’s milliDelta robot dimensions are 15 mm x 15 mm x 20 mm and it weighs just 430 milligrams (1 milligram is 1/1000thof a gram).   Despite its tiny dimensions, however it has the capacity to move 1.3 grams, which could be hugely significant for micro-surgery.  This model can move around its 7 cubic millimeter workspace within around 5 micro-meters of precision.

What will impress you more perhaps is its speed, reaching velocities of 0.45 m/s and it accelerates at 215 m/s2.  For the engineers reading, the milliDelta can follow repeating patterns at a frequency of up to 75 Hz.

This static robot performs repeated movements so fast that they become invisible.  Harvard School of Engineering and Applied Sciences and Wyss Institute for Biologically Inspired Engineering’s half-minute video demonstrates high velocity precision movements, within 1-2 millimetre ranges.

MilliDelta’s action is driven by piezoelectric actuators.  The rest of the robot has been designed for what is termed monolithic fabrication; a monolithic interconnected circuit (IC) is one that has all the components of a circuit and any interconnections combinedonto a single base. These are popular, because they are the cheapest type of integrated circuits. 

Each piece is comprised of a sandwich of carbon fibre for the structural elements, Kapton film for flexibility, (‘flexures’) and heat- and pressure-activated adhesive, but the Harvard researchers say that there are different ways to build this mini-Robot.  

Future Applications on the milliDelta

Pick-and-place tasks for manufacturing of products with intricate components are an obvious application for the milliDelta, circuit boards fabrication being a classic example.   However, the trend towards micro-robotics, such as bio-mimicry designin flying robots mean there are countless micro-factorybenefits also. In medicine, microsurgical assistance could see extensive use of this robotics equipment.  The milliDelta robot could eliminate the impact of the surgeon’s natural tremors, which could make eye or brain surgery, for instance, much less risky.  The first such delta robot was used for high speed packaging in a chocolate factory as early as 1985, designed by Professor Raymond Clavel, a professor at EPFL.

This development required a robot with ultra-lightweight arms to move the pralines, each of which weighed around ten grams each.  After experimenting at home with his wife’s knitting needs, Professor Clavel finally came up with a design comprising three articulated arms, with the motor at the base.   You can read more about this original light-weight and fast moving prototype delta robot here.

Of course, there will be many potential uses not even yet imagined, but we would love to hear if you are involved in any similar projects, or perhaps are a business that can see how this automating robotics equipmentcould benefit your repetitive and intricate business processes.  Leave us your comments below, we’d love to hear them.

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