In what was a pretty scrappy game throughout, the Imps went into the break a goal down with Tom Phipp drilling his side in front with a powerful effort from 25 yards.
The City heads didn't drop though and, having hit the woodwork twice through Alan Power and Nicky Nicolau, Robinson secured a deserved point when he fired home following a cross from fellow substitute Colin Larkin.
There were two changes for the Imps for this Blue Square Bet Premier game at Ebbsfleet United with Paul Farman returning in goal whilst new loan signing Jake Thomson came in for his debut with the injured Vadaine Oliver missing out. Thomson slotted into midfield allowing skipper Alan Power to line-up behind Jamie Taylor in attack.
There was a welcome return to the squad, meanwhile, for Conal Platt who was back in the fold for the first time in 11 months and he was joined on the bench by Bradley Barraclough following his return from a loan spell at Gainsborough Trinity.
City kicked off and were the first to push forward with a foul on Jake Sheridan bringing about a free-kick in the second minute but Power's delivery sailed over a packed box and out for a goal-kick.
The next foray forward saw Jamie Taylor pressure Paul Lorraine into conceding a corner and when this was played low by Nicky Nicolau to Power the latter saw his curling effort crash against the bar before bouncing out. Before the resultant goal-kick could be taken Sheridan required treatment before being helped to the touchline in a somewhat groggy state.
Sheridan returned following a couple of minutes on the sidelines before Dan Gray was spoken to by referee Graham Horwood following a meaty challenge on Neil Barrett. Andrew Boyce was then forced to clear his lines as the home side pressed for the first time.
At the other end a long Gray throw-in was hurriedly cleared by the United defence before Taylor fizzed a 25-yard effort wide of the target. Debutant Thomson was then upended close to the corner flag following a clever run from midfield; Power's deep delivery though was claimed by home stopper Preston Edwards.
As the half approached its midway point, an Ebbsfleet attack ended with a cross finding its way to Lorraine who took a touch before being denied by a brave save by Paul Farman who appeared to take a blow to the side of the head as he denied the home skipper. He resumed his duties after a brief spell of treatment from Kev Oxby.
Oxby was back on the field a couple of minutes later when Sheridan was grounded for a second time. Again he looked to be in a dazed condition and was replaced by Colin Larkin with the clock in its 27th minute. The change saw Thomson move to the right with Power dropping back into midfield with Larkin slotting into the role behind Taylor.
Two City corners quickly followed whilst another, following good work by Larkin and Thomson, brough about another break in play with Edwards going to ground when Nicolau's delivery was played into the mix.
Play switched to the other end a couple of minutes later and when a quick throw-in was taken to Tom Phipp, the Ebbsfleet man unleashed a shot from range which flew past the unsighted Farman before nestling in the back of the net for an undeserved advantage.
Shortly after the restart Nathan Elder led with an arm on Boyce only to escape with a yellow card and the experienced striker had a quick chance to capitalise on what looked to be a lucky escape when he came close to connecting with a low Lanre Azeez centre as the home side pressed for a second.
Garner then got a great block in to deny Liam Enver-Marum whose appeals for handball and a penalty were waved away by referee Horwood, who shortly afterwards booked Lorraine for a late challenge on Taylor as the Fourth Official prepared to indicate that a minimum of three minutes were to be added on.
Craig Stone became the third Ebbsfleet player to see yellow as he left a foot in on Nicolau before the referee brought the half to a close.
HT: Ebbsfleet 1 Imps 0
A change at the break saw Bradley Barraclough replace Scott Garner, who had picked up a dead-leg towards the end of the opening period, but seconds after play restarted, referee Horwood cautioned the City substitute who, in his eyes, had entered the field of play without permission. It's safe to say that manager David Holdsworth was somewhat perplexed and angry with the decision.
With Gray dropping back to central defence, Barraclough partnered Taylor up front in a 4-4-2 formation and he was quickly advancing forward, winning a corner which came to nothing. As Ebbsfleet reponded, Robson was harshly booked for a block on Azeez. The cards continued a couple of minutes later with Boyce seeing yellow for a foul on Enver-Marum.
City were denied by the woodwork for a second time in the 58th minute when Nicolau let fly from range only to see his right-footed strike crash against the bar and out to safety. A couple of minutes later Power was closed down on the edge of the box after a ball was squared to him by Barraclough.
At the other end Enver-Marum was cautioned for diving under a Miller challenge for the seventh booking of the afternoon and five minutes later Thomson almost became the eighth but his challenge on Ashley Carew ended in just a free-kick which the United man curled well over.
Conner Robinson for Nicky Nicolau was the Imps' final change of the game with 17 minutes on the clock whilst a couple of minutes later Thomson was booked for a late block on scorer Phipp.
Robinson was quickly in the action, drawing a foul out of Carew on the right, but when Power swung in the free-kick, Miller saw his header across the box hacked off the line as the hosts breathed a sigh of relief.
With the game now in its last 10 minutes Taylor was picked out by Larkin only for his header to go straight into Edwards' gloves. At the other end Enver-Marum, looking suspiciously offside, advanced forward before firing well wide.
A foul on Taylor by Lorraine gave the Imps another chance from a set-piece in a central position but Taylor's effort from the dead-ball crashed straight against the wall before Power's follow-up effort went straight through to Edwards.
An Ebbsfleet counter-attack then ended with Farman pushing a Carew effort behind for the hosts' first corner of the game. As City responded a Phipp trip on Miller saw him see yellow before Barraclough was denied a sight of goal following good work by Taylor.
Liam Bellamy for Ashley Carew was Ebbsfleet's first change as manager Liam Daish looked to eat some seconds up before the game reached four minutes of added time.
With Boyce pushed forward in a last ditch attempt to snatch a leveller, good work from Robinson saw him win a corner which was headed off target by Barraclough. City kept pressing though and with added time three minutes old, Robinson popped up with a dramatic leveller.
The goal came after Larkin was picked out by Gray from a throw-in down the right flank and when his cross was played into the box there was the teenage striker to rifle home from 15 yards out.
City were still forced to defend a corner before referee Horwood blew for time with the Imps finishing a scappy game with their third successive 1-1 draw.
FT: Ebbsfleet 1 Imps 1
City: Paul Farman, Tom Miller, Andrew Boyce, Scott Garner, Paul Robson, Dan Gray, Jake Thomson, Nicky Nicolau, Jake Sheridan, Alan Power, Jamie Taylor.
subs: Conal Platt, Bradley Barraclough (for Garner h/t), Colin Larkin (for Sheridan 27), Conner Robinson (for Nicolau 73), David Preece.
goals: Robinson (90+3)
bookings: Barracough (46), Robson (51), Boyce (53), Thomson (75)
Ebbsfleet: Preston Edwards, Craig Stone, Phil Walsh, Paul Lorraine, Liam Enver-Marum, Nathan Elder, Tom Phipp, Joe Howe, Neil Barrett, Lanre Azeez, Ashley Carew.
subs: Ryan Blake, Liam Bellamy (for Carew 88), Adam Williams, Giannoulis Fakinos, Lucas Menz.
goals: Phipp (36)
bookings: Elder (37), Edwards (45), Stone (45+3), Enver-Marum (65), Phipp (86)
Referee: Graham Horwood
Assistants: Neil West & Andrew Aylott
Fourth Official: David Spain