How a Robot Actuator Controls Force and Speed with Gears
This patent describes a compact robot actuator that uses a special gear system and two motors with different electrical resistance to precisely control both the force and speed applied to a robotic arm or tool.
Original patent title: “High performance differential actuator for robotic interaction tasks”
This patent describes a compact robot actuator that uses a special gear system and two motors with different electrical resistance to precisely control both the force and speed applied to a robotic arm or tool. Granted to Societe de Commercialisation des Produits de la Recherche Appliquee SOCPRA in 2012 with 37 claims and 5 forward citations, and it is expected to expire in 2027.
Coverage
What does this patent actually cover?
The patent details a "mechanical differential actuator" (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1) designed for interacting with a "mechanical load." It uses a "mechanical differential" (like a special gearbox) with three connection points, called "interaction ports." A "first transducer" (like a motor or brake) with "low impedance" connects to one port, mainly controlling force (Claim 4). A "second transducer" (like another motor) with "high impedance" connects to a second port, mainly controlling speed (Claim 10). The third port connects to the "load," which is what the robot needs to move or apply force to. The clever part is that the second transducer's high impedance is so large that it "does not influence significantly" the overall behavior of the actuator (Claim 1), allowing for independent and precise control of both force and speed at the load. For example, a robot arm could use this to gently pick up a delicate object while also moving it quickly and precisely.
The gap
What does this patent NOT cover?
- Does not cover actuators that lack a mechanical differential with three distinct interaction ports.
- Does not cover systems where the second transducer's impedance significantly affects the overall equivalent impedance of the actuator (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1).
- Does not cover actuators where the first transducer is not primarily a source of force or the second transducer is not primarily a source of speed, as described (ClaimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → 4, 10).
- Does not cover purely electronic or hydraulic control systems that do not incorporate a mechanical differential.
- Does not cover actuators that cannot control both force and speed at the load.
- Does not cover systems where the mechanical differential is not compact or cannot transfer large forces relative to its volume.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The noveltynoveltyThe requirement that an invention be different from anything publicly known before its priority date.Read more → lies in combining a mechanical differential with two transducers having vastly different impedances. Specifically, the second transducer's high impedance is engineered to be so large that it isolates the overall actuator's behavior from its own, allowing for independent and precise control of both force and speed at the output load, all within a compact design.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Collaborative robot arms (cobots)
Surgical robots
Haptic feedback devices
Industrial automation manipulators
Exoskeletons for assistance or rehabilitation
Why it matters
The bigger picture
This technology is important for creating more advanced and versatile robots. By allowing precise control over both force and speed in a compact design, it enables robots to perform delicate tasks, interact safely with humans, and operate efficiently in tight spaces. This is crucial for applications ranging from manufacturing to medical robotics.
Filed
March 30, 2007
Granted
June 26, 2012
Market context
Who's building on this
Companies in this space
Societe de Commercialisation des Produits de la Recherche Appliquee SOCPRA, a technology transfer organization, is the assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →. The inventors are associated with Université de Sherbrooke, suggesting the technology originated in academic research. Companies in advanced robotics, particularly those developing collaborative robots (cobots) or haptic feedback systems, would be interested in such compact, high-performance actuators. This includes firms like KUKA, ABB, Universal Robots, and specialized haptics companies.
Market impact
This type of actuator design contributes to the development of more sophisticated robotic systems. By enabling compact structures that can transfer large forces while precisely controlling both force and speed, it supports the creation of robots capable of delicate manipulation, safe human-robot interaction (cobots), and high-performance industrial automation. It addresses a fundamental challenge in robotics: achieving both power and precision in a small footprint, which is critical for expanding robot capabilities and applications.
Claim 1 — Plain English
What this patent covers
The patent details a "mechanical differential actuator" (Claim 1) designed for interacting with a "mechanical load." It uses a "mechanical differential" (like a special gearbox) with three connection points, called "interaction ports." A "first transducer" (like a motor or brake) with "low impedance" connects to one port, mainly controlling force (Claim 4). A "second transducer" (like another motor) with "high impedance" connects to a second port, mainly controlling speed (Claim 10). The third port connects to the "load," which is what the robot needs to move or apply force to. The clever part is that the second transducer's high impedance is so large that it "does not influence significantly" the overall behavior of the actuator (Claim 1), allowing for independent and precise control of both force and speed at the load. For example, a robot arm could use this to gently pick up a delicate object while also moving it quickly and precisely.
The clever bit
The novelty lies in combining a mechanical differential with two transducers having vastly different impedances. Specifically, the second transducer's high impedance is engineered to be so large that it isolates the overall actuator's behavior from its own, allowing for independent and precise control of both force and speed at the output load, all within a compact design.
What it does not cover
- Does not cover actuators that lack a mechanical differential with three distinct interaction ports.
- Does not cover systems where the second transducer's impedance significantly affects the overall equivalent impedance of the actuator (Claim 1).
- Does not cover actuators where the first transducer is not primarily a source of force or the second transducer is not primarily a source of speed, as described (Claims 4, 10).
- Does not cover purely electronic or hydraulic control systems that do not incorporate a mechanical differential.
- Does not cover actuators that cannot control both force and speed at the load.
- Does not cover systems where the mechanical differential is not compact or cannot transfer large forces relative to its volume.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
PatentBrief Score
Impact Score
Moderate
Citation count
16/40
Early citations
Claim breadth
20/20
Very broad protection
Recency
5/20
Granted 10–20 years ago
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$8K – $26K
Midpoint $16K · expired or expiring · industry ×0.9
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Patent Claims
0 independent claims · 1 dependent
Claims are the legal boundaries of the patent. An independent claim stands alone. A dependent claim adds limitations to its parent, narrowing — but not broadening — the scope.
The original legal language
Original claims
37 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Lauria, M., Giguére, P., Lavoie, M., Michaud, F., Legault, M., & Gagnon, F. (2012). How a Robot Actuator Controls Force and Speed with Gears (U.S. Patent No. 8,209,052). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/8209052/high-performance-differential-actuator-for-robotic-interaction-tasks
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How a Robot Actuator Controls Force and Speed with Gears cover?
This patent describes a compact robot actuator that uses a special gear system and two motors with different electrical resistance to precisely control both the force and speed applied to a robotic arm or tool.
Who owns patent US 8209052?
Societe de Commercialisation des Produits de la Recherche Appliquee SOCPRA owns this patent, granted in 2012.
When does this patent expire?
This patent is expected to expire on March 30, 2027, when the invention enters the public domain.
What is patent US 8209052 cited by?
This patent has been cited by 5 later patents that build on its ideas.
What problem does this patent solve?
This technology is important for creating more advanced and versatile robots. By allowing precise control over both force and speed in a compact design, it enables robots to perform delicate tasks, interact safely with humans, and operate efficiently in tight spaces. This is crucial for applications ranging from manufacturing to medical robotics.
What does this patent NOT cover?
Does not cover actuators that lack a mechanical differential with three distinct interaction ports.
Patent monitoring