{
  "patent_number": "US 8209052",
  "country": "US",
  "title": "How a Robot Actuator Controls Force and Speed with Gears",
  "original_title": "High performance differential actuator for robotic interaction tasks",
  "summary": "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.",
  "what_it_does": "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.",
  "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."
  ],
  "filed": "2007-03-30",
  "granted": "2012-06-26",
  "expires": "2027-03-30",
  "status": "active",
  "holder": "Societe de Commercialisation des Produits de la Recherche Appliquee SOCPRA",
  "holder_url": "https://patentbrief.org/company/societe-de-commercialisation-des-produits-de-la-recherche-appliquee-socpra",
  "inventors": [
    {
      "name": "Michel Lauria",
      "url": "https://patentbrief.org/inventor/michel-lauria"
    },
    {
      "name": "Patrick Giguére",
      "url": "https://patentbrief.org/inventor/patrick-gigure"
    },
    {
      "name": "Marc-André Lavoie",
      "url": "https://patentbrief.org/inventor/marc-andr-lavoie"
    },
    {
      "name": "François Michaud",
      "url": "https://patentbrief.org/inventor/franois-michaud"
    },
    {
      "name": "Marc-Antoine Legault",
      "url": "https://patentbrief.org/inventor/marc-antoine-legault"
    },
    {
      "name": "Frédéric Gagnon",
      "url": "https://patentbrief.org/inventor/frdric-gagnon"
    }
  ],
  "times_cited": 5,
  "tags": [
    "robotics",
    "mechanical",
    "automation",
    "consumer_electronics",
    "medical_devices"
  ],
  "abstract": "The mechanical differential actuator according to the present invention comprises a mechanical differential having three mechanicals ports. A first transducer with a low impedance is coupled to a first port, a second transducer with a high impedance is coupled to a second port, and the mechanical load is coupled to the third port. The mechanical differential actuator enables controlling a force and a speed at a load coupled thereto through a known relation between the force and the speed. Moreover, the mechanical differential actuator presents a compact structure enabling the transfer of a large force relative to its volume.",
  "url": "https://patentbrief.org/patent/us/8209052/high-performance-differential-actuator-for-robotic-interaction-tasks",
  "markdown_url": "https://patentbrief.org/patent/us/8209052/high-performance-differential-actuator-for-robotic-interaction-tasks/md",
  "google_patents_url": "https://patents.google.com/patent/US8209052",
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}